page 16 of 17
(171)Searching for Sub-GeV dark matter in the galactic centre using Hyper-Kamiokande
  • Nicole F. Bell,
  • Matthew J. Dolan,
  • Sandra Robles
Journal of Cosmology and Astroparticle Physics (09/2020) doi:10.1088/1475-7516/2020/09/019
abstract + abstract -

Indirect detection of dark matter via its annihilation products is a key technique in the search for dark matter in the form of weakly interacting massive particles (WIMPs). Strong constraints exist on the annihilation of WIMPs to highly visible Standard Model final states such as photons or charged particles. In the case of s-wave annihilation, this typically eliminates thermal relic cross sections for dark matter of mass below Script O(10) GeV . However, such limits typically neglect the possibility that dark matter may annihilate to assumed invisible or hard-to-detect final states, such as neutrinos. This is a difficult paradigm to probe due to the weak neutrino interaction cross section. Considering dark matter annihilation in the Galactic halo, we study the prospects for indirect detection using the Hyper-Kamiokande (HyperK) neutrino experiment, for dark matter of mass below 1 GeV . We undertake a dedicated simulation of the HyperK detector, which we benchmark against results from the similar Super-Kamiokande experiment and HyperK physics projections. We provide projections for the annihilation cross-sections that can be probed by HyperK for annihilation to muon or neutrino final states, and discuss uncertainties associated with the dark matter halo profile. For neutrino final states, we find that HyperK is sensitive to thermal annihilation cross-sections for dark matter with mass around 20 MeV, assuming an NFW halo profile. We also discuss the effects of neutron tagging, and prospects for improving the reach at low mass.

(170)How attractive is the isotropic attractor solution of axion-SU(2) inflation?
  • Ira Wolfson,
  • Azadeh Maleknejad,
  • Eiichiro Komatsu
Journal of Cosmology and Astroparticle Physics (09/2020) doi:10.1088/1475-7516/2020/09/047
abstract + abstract -

The key to the phenomenological success of inflation models with axion and SU(2) gauge fields is the isotropic background of the SU(2) field. Previous studies showed that this isotropic background is an attractor solution during inflation starting from anisotropic (Bianchi type I) spacetime; however, not all possible initial anisotropic parameter space was explored. In this paper, we explore more generic initial conditions without assuming the initial slow-roll dynamics. We find some initial anisotropic parameter space which does not lead to the isotropic background, but to violation of slow-roll conditions, terminating inflation prematurely. The basin of attraction increases when we introduce another scalar field acting as inflaton and make the axion-SU(2) system a spectator sector. Therefore, the spectator axion-SU(2) model is phenomenologically more attractive.

(169)Two-loop renormalization group equations for right-handed neutrino masses and phenomenological implications
  • Alejandro Ibarra,
  • Patrick Strobl,
  • Takashi Toma
Physical Review D (09/2020) doi:10.1103/PhysRevD.102.055011
abstract + abstract -

We calculate the two-loop beta functions of the right-handed neutrino mass matrix in the Standard Model extended with right-handed neutrinos. We show that two-loop quantum effects induced by the heavier right-handed neutrinos can induce sizable contributions (sometimes dominant) to the physical masses of the lighter right-handed neutrinos. These effects can significantly affect the masses of the active neutrinos in the seesaw mechanism and the low-energy phenomenology.

(168)Jet substructure from dark sector showers
  • Timothy Cohen,
  • Joel Doss,
  • Marat Freytsis
Journal of High Energy Physics (09/2020) doi:10.1007/JHEP09(2020)118
abstract + abstract -

We examine the robustness of collider phenomenology predictions for a dark sector scenario with QCD-like properties. Pair production of dark quarks at the LHC can result in a wide variety of signatures, depending on the details of the new physics model. A particularly challenging signal results when prompt production induces a parton shower that yields a high multiplicity of collimated dark hadrons with subsequent decays to Standard Model hadrons. The final states contain jets whose substructure encodes their non-QCD origin. This is a relatively subtle signature of strongly coupled beyond the Standard Model dynamics, and thus it is crucial that analyses incorporate systematic errors to account for the approximations that are being made when modeling the signal. We estimate theoretical uncertainties for a canonical substructure observable designed to be sensitive to the gauge structure of the underlying object, the two-point energy correlator e2(β ), by computing envelopes between resummed analytic distributions and numerical results from Pythia. We explore the separability against the QCD background as the confinement scale, number of colors, number of flavors, and dark quark masses are varied. Additionally, we investigate the uncertainties inherent to modeling dark sector hadronization. Simple estimates are provided that quantify one's ability to distinguish these dark sector jets from the overwhelming QCD background. Such a search would benefit from theory advances to improve the predictions, and the increase in statistics using the data to be collected at the high luminosity LHC.

(167)The convolutional double copy: a case study with a point
  • Andrés Luna,
  • Silvia Nagy,
  • Chris D. White
Journal of High Energy Physics (09/2020) doi:10.1007/JHEP09(2020)062
abstract + abstract -

The double copy relates scattering amplitudes in gauge and gravity theories. It has also been extended to classical solutions, and a number of approaches have been developed for doing so. One of these involves expressing fields in a variety of (super-)gravity theories in terms of convolutions of gauge fields, including also BRST ghost degrees of freedom that map neatly to their corresponding counterparts in gravity. In this paper, we spell out how to use the convolutional double copy to map gauge and gravity solutions in the manifest Lorenz and de Donder gauges respectively. We then apply this to a particular example, namely the point charge in pure gauge theory. As well as clarifying how to use the convolutional approach, our results provide an alternative point of view on a recent discussion concerning whether point charges map to the Schwarzschild solution, or the more general two-parameter JNW solution, which includes a dilaton field. We confirm the latter.

(166)Connecting Optical Morphology, Environment, and H I Mass Fraction for Low-redshift Galaxies Using Deep Learning
  • John F. Wu
The Astrophysical Journal (09/2020) doi:10.3847/1538-4357/abacbb
abstract + abstract -

A galaxy's morphological features encode details about its gas content, star formation history, and feedback processes, which play important roles in regulating its growth and evolution. We use deep convolutional neural networks (CNNs) to learn a galaxy's optical morphological information in order to estimate its neutral atomic hydrogen (H I) content directly from Sloan Digital Sky Survey (SDSS) gri image cutouts. We are able to accurately predict a galaxy's logarithmic H I mass fraction, ${ \mathcal M }\equiv \mathrm{log}({M}_{{\rm{H}}{\rm\small{I}}}/{M}_{\star })$ , by training a CNN on galaxies in the Arecibo Legacy Fast ALFA Survey (ALFALFA) 40% sample. Using pattern recognition, we remove galaxies with unreliable ${ \mathcal M }$ estimates. We test CNN predictions on the ALFALFA 100%, extended Galaxy Evolution Explorer Arecibo SDSS Survey, and Nançay Interstellar Baryons Legacy Extragalactic Survey catalogs, and find that the CNN consistently outperforms previous estimators. The H I-morphology connection learned by the CNN appears to be constant in low- to intermediate-density galaxy environments, but it breaks down in the highest-density environments. We also use a visualization algorithm, Gradient-weighted Class Activation Maps, to determine which morphological features are associated with low or high gas content. These results demonstrate that CNNs are powerful tools for understanding the connections between optical morphology and other properties, as well as for probing other variables, in a quantitative and interpretable manner.

(165)Prebiotically Plausible Organocatalysts Enabling a Selective Photoredox α-Alkylation of Aldehydes on the Early Earth
  • A. C. Closs,
  • E. Fuks,
  • M. Bechtel,
  • O. Trapp
Chem. Eur. J. (08/2020) doi:10.1002/chem.202001514
abstract + abstract -

Organocatalysis is a powerful approach to extend and (enantio-) selectively modify molecular structures. Adapting this concept to the Early Earth scenario offers a promising solution to explain their evolution into a complex homochiral world. Herein, we present a class of imidazolidine-4-thione organocatalysts, easily accessible from simple molecules available on an Early Earth under highly plausible prebiotic reaction conditions. These imidazolidine-4-thiones are readily formed from mixtures of aldehydes or ketones in presence of ammonia, cyanides and hydrogen sulfide in high selectivity and distinct preference for individual compounds of the resulting catalyst library. These organocatalysts enable the enantioselective α-alkylation of aldehydes under prebiotic conditions and show activities that correlate with the selectivity of their formation. Furthermore, the crystallization of single catalysts as conglomerates opens the pathway for symmetry breaking.

(164)Candidate periodically variable quasars from the Dark Energy Survey and the Sloan Digital Sky Survey
  • Yu-Ching Chen,
  • Xin Liu,
  • Wei-Ting Liao,
  • A.Miguel Holgado,
  • Hengxiao Guo
  • +60
  • Robert A. Gruendl,
  • Eric Morganson,
  • Yue Shen,
  • Kaiwen Zhang,
  • Tim M.C. Abbott,
  • Michel Aguena,
  • Sahar Allam,
  • Santiago Avila,
  • Emmanuel Bertin,
  • Sunayana Bhargava,
  • David Brooks,
  • David L. Burke,
  • Aurelio Carnero Rosell,
  • Daniela Carollo,
  • Matias Carrasco Kind,
  • Jorge Carretero,
  • Matteo Costanzi,
  • Luiz N. da Costa,
  • Tamara M. Davis,
  • Juan De Vicente,
  • Shantanu Desai,
  • H. Thomas Diehl,
  • Peter Doel,
  • Spencer Everett,
  • Brenna Flaugher,
  • Douglas Friedel,
  • Joshua Frieman,
  • Juan García-Bellido,
  • Enrique Gaztanaga,
  • Karl Glazebrook,
  • Daniel Gruen,
  • Gaston Gutierrez,
  • Samuel R. Hinton,
  • Devon L. Hollowood,
  • David J. James,
  • Alex G. Kim,
  • Kyler Kuehn,
  • Nikolay Kuropatkin,
  • Geraint F. Lewis,
  • Christopher Lidman,
  • Marcos Lima,
  • Marcio A.G. Maia,
  • Marisa March,
  • Jennifer L. Marshall,
  • Felipe Menanteau,
  • Ramon Miquel,
  • Antonella Palmese,
  • Francisco Paz-Chinchón,
  • Andrés A. Plazas,
  • Eusebio Sanchez,
  • Michael Schubnell,
  • Santiago Serrano,
  • Ignacio Sevilla-Noarbe,
  • Mathew Smith,
  • Eric Suchyta,
  • Molly E.C. Swanson,
  • Gregory Tarle,
  • Brad E. Tucker,
  • Tamas Norbert Varga,
  • Alistair R. Walker
  • (less)
Mon.Not.Roy.Astron.Soc. (08/2020) e-Print:2008.12329 doi:10.1093/mnras/staa2957
abstract + abstract -

Periodically variable quasars have been suggested as close binary supermassive black holes. We present a systematic search for periodic light curves in 625 spectroscopically confirmed quasars with a median redshift of 1.8 in a 4.6 deg^2 overlapping region of the Dark Energy Survey Supernova (DES-SN) fields and the Sloan Digital Sky Survey Stripe 82 (SDSS-S82). Our sample has a unique 20-yr long multicolour (griz) light curve enabled by combining DES-SN Y6 observations with archival SDSS-S82 data. The deep imaging allows us to search for periodic light curves in less luminous quasars (down to r ∼23.5 mag) powered by less massive black holes (with masses ≳ 10^8.5M_⊙) at high redshift for the first time. We find five candidates with significant (at >99.74 per cent single-frequency significance in at least two bands with a global p-value of ∼7 × 10^−4–3 × 10^−3 accounting for the look-elsewhere effect) periodicity with observed periods of ∼3–5 yr (i.e. 1–2 yr in rest frame) having ∼4–6 cycles spanned by the observations. If all five candidates are periodically variable quasars, this translates into a detection rate of |${\sim }0.8^{+0.5}_{-0.3}$| per cent or |${\sim }1.1^{+0.7}_{-0.5}$| quasar per deg^2. Our detection rate is 4–80 times larger than those found by previous searches using shallower surveys over larger areas. This discrepancy is likely caused by differences in the quasar populations probed and the survey data qualities. We discuss implications on the future direct detection of low-frequency gravitational waves. Continued photometric monitoring will further assess the robustness and characteristics of these candidate periodic quasars to determine their physical origins.

(163)ALMA unveils wider environment of distant red protocluster core
  • R. J. Ivison,
  • A. D. Biggs,
  • M. Bremer,
  • V. Arumugam,
  • L. Dunne
Monthly Notices of the Royal Astronomical Society (08/2020) doi:10.1093/mnras/staa1802
abstract + abstract -

We report observations with the Atacama Large Millimetre Array (ALMA) of six submillimetre galaxies (SMGs) within 3 arcmin of the Distant Red Core (DRC) at z = 4.0, a site of intense cluster-scale star formation, first reported by Oteo et al. We find new members of DRC in three SMG fields; in two fields, the SMGs are shown to lie along the line of sight towards DRC; one SMG is spurious. Although at first sight this rate of association is consistent with earlier predictions, associations with the bright SMGs are rarer than expected, which suggests caution when interpreting continuum overdensities. We consider the implications of all 14 confirmed DRC components passing simultaneously through an active phase of star formation. In the simplest explanation, we see only the tip of the iceberg in terms of star formation and gas available for future star formation, consistent with our remarkable finding that the majority of newly confirmed DRC galaxies are not the brightest continuum emitters in their immediate vicinity. Thus, while ALMA continuum follow-up of SMGs identifies the brightest continuum emitters in each field, it does not necessarily reveal all the gas-rich galaxies. To hunt effectively for protocluster members requires wide and deep spectral-line imaging to uncover any relatively continuum-faint galaxies that are rich in atomic or molecular gas. Searching with short-baseline arrays or single-dish facilities, the true scale of the underlying gas reservoirs may be revealed.

(162)Astrometric study of Gaia DR2 stars for interstellar communication
  • Naoki Seto,
  • Kazumi Kashiyama
International Journal of Astrobiology (08/2020) doi:10.1017/S147355042000004X
abstract + abstract -

We discuss the prospects of high precision pointing of our transmitter to habitable planets around Galactic main sequence stars. For an efficient signal delivery, the future sky positions of the host stars should be appropriately extrapolated with accuracy better than the beam opening angle $\Theta$ of the transmitter. Using the latest data release (DR2) of Gaia, we estimate the accuracy of the extrapolations individually for $4.7\times 10^7$ FGK stars, and find that the total number of targets could be $\sim 10^7$ for the accuracy goal better than 1". Considering the pairwise nature of communication, our study would be instructive also for SETI (Search for Extraterrestrial Intelligence), not only for sending signals outward.

(161)Hadronic cross section of e<SUP>+</SUP>e<SUP>-</SUP> annihilation at bottomonium energy region
  • Xiang-Kun Dong,
  • Xiao-Hu Mo,
  • Ping Wang,
  • Chang-Zheng Yuan
Chinese Physics C (08/2020) doi:10.1088/1674-1137/44/8/083001
abstract + abstract -

The Born cross section and dressed cross section of $ e^+e^-\to b\bar{b} $?--> and the total hadronic cross section in $ e^+e^- $?--> annihilation in the bottomonium energy region are calculated based on the $ R_b $?--> values measured by the BaBar and Belle experiments. The data are used to calculate the vacuum polarization factors in the bottomonium energy region, and to determine the resonant parameters of the vector bottomonium(-like) states $ Y(10750) $?--> , $ \Upsilon(5S) $?--> , and $ \Upsilon(6S) $?--> . * Supported in part by National Natural Science Foundation of China (NSFC) (11521505, 11475187, 11375206); Key Research Program of Frontier Sciences, CAS, (QYZDJ-SSW-SLH011); the CAS Center for Excellence in Particle Physics (CCEPP); and the Munich Institute for Astro- and Particle Physics (MIAPP) which is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy-EXC-2094-390783311

(160)Three-dimensional models of core-collapse supernovae from low-mass progenitors with implications for Crab
  • G. Stockinger,
  • H. -T. Janka,
  • D. Kresse,
  • T. Melson,
  • T. Ertl
  • +7
  • M. Gabler,
  • A. Gessner,
  • A. Wongwathanarat,
  • A. Tolstov,
  • S. -C. Leung,
  • K. Nomoto,
  • A. Heger
  • (less)
Monthly Notices of the Royal Astronomical Society (08/2020) doi:10.1093/mnras/staa1691
abstract + abstract -

We present 3D full-sphere supernova simulations of non-rotating low-mass (∼9 M) progenitors, covering the entire evolution from core collapse through bounce and shock revival, through shock breakout from the stellar surface, until fallback is completed several days later. We obtain low-energy explosions (∼0.5-1.0 × 1050 erg) of iron-core progenitors at the low-mass end of the core-collapse supernova (LMCCSN) domain and compare to a super-AGB (sAGB) progenitor with an oxygen-neon-magnesium core that collapses and explodes as electron-capture supernova (ECSN). The onset of the explosion in the LMCCSN models is modelled self-consistently using the VERTEX-PROMETHEUS code, whereas the ECSN explosion is modelled using parametric neutrino transport in the PROMETHEUS-HOTB code, choosing different explosion energies in the range of previous self-consistent models. The sAGB and LMCCSN progenitors that share structural similarities have almost spherical explosions with little metal mixing into the hydrogen envelope. A LMCCSN with less second dredge-up results in a highly asymmetric explosion. It shows efficient mixing and dramatic shock deceleration in the extended hydrogen envelope. Both properties allow fast nickel plumes to catch up with the shock, leading to extreme shock deformation and aspherical shock breakout. Fallback masses of $\mathord {\lesssim }\, 5\, \mathord {\times }\, 10^{-3}$ M have no significant effects on the neutron star (NS) masses and kicks. The anisotropic fallback carries considerable angular momentum, however, and determines the spin of the newly born NS. The LMCCSN model with less second dredge-up results in a hydrodynamic and neutrino-induced NS kick of >40 km s-1 and a NS spin period of ∼30 ms, both not largely different from those of the Crab pulsar at birth.

(159)Gravitational-wave constraints on an effective-field-theory extension of general relativity
  • Noah Sennett,
  • Richard Brito,
  • Alessandra Buonanno,
  • Victor Gorbenko,
  • Leonardo Senatore
Physical Review D (08/2020) doi:10.1103/PhysRevD.102.044056
abstract + abstract -

Gravitational-wave observations of coalescing binary systems allow for novel tests of the strong-field regime of gravity. Using data from the Gravitational Wave Open Science Center (GWOSC) of the LIGO and Virgo detectors, we place the first constraints on an effective-field-theory based extension of general relativity, in which only higher-order curvature terms are added to the Einstein-Hilbert action. We construct gravitational-wave templates describing the quasicircular, adiabatic inspiral phase of binary black holes in this extended theory of gravity. Then, after explaining how to properly take into account the region of validity of the effective field theory when performing tests of general relativity, we perform Bayesian model selection using the two lowest-mass binary-black-hole events reported to date by LIGO and Virgo—GW151226 and GW170608—and constrain this theory with respect to general relativity. We find that these data disfavor the appearance of new physics on distance scales around ∼150 km . Finally, we describe a general strategy for improving constraints as more observations will become available with future detectors on the ground and in space.

(158)ɛ<SUP>'</SUP>/ɛ in the Standard Model at the Dawn of the 2020s
  • Jason Aebischer,
  • Christoph Bobeth,
  • Andrzej J. Buras
European Physical Journal C (08/2020) doi:10.1140/epjc/s10052-020-8267-1
abstract + abstract -

We reanalyse the ratio ɛ'/ɛ in the Standard Model (SM) using most recent hadronic matrix elements from the RBC-UKQCD collaboration in combination with most important NNLO QCD corrections to electroweak penguin contributions and the isospin-breaking corrections. We illustrate the importance of the latter by using their latest estimate from chiral perturbation theory (ChPT) based on the octet approximation for lowest-lying mesons and a very recent estimate in the nonet scheme that takes into account the contribution of η0. We find (ɛ'/ɛ)SM(8 )=(17.4 ±6.1 ) ×10-4 and (ɛ'/ɛ)SM(9 )=(13.9 ±5.2 ) ×10 -4 , respectively. Despite a very good agreement with the measured value (ɛ') exp=(16.6 ±2.3 ) ×10-4 , the large error in (ɛ') SM still leaves room for significant new physics (BSM) contributions to this ratio. We update the 2018 master formula for (ɛ') BSM valid in any extension beyond the SM without additional light degrees of freedom. We provide new values of the penguin parameters B6(1 /2 )(μ ) and B8(3 /2 )(μ ) at the μ -scales used by the RBC-UKQCD collaboration and at lower scales O (1 GeV) used by ChPT and Dual QCD (DQCD). We present semi-analytic formulae for (ɛ') SM in terms of these parameters and Ω^eff that summarizes isospin-breaking corrections to this ratio. We stress the importance of lattice calculations of the O (αem) contributions to the hadronic matrix elements necessary for the removal of renormalization scheme dependence at O (αem) in the present analyses of ɛ'/ɛ.

(157)Isospin-breaking in ɛ<SUP>'</SUP>/ɛ : impact of η<SUB>0</SUB> at the dawn of the 2020s
  • Andrzej J. Buras,
  • Jean-Marc Gérard
European Physical Journal C (08/2020) doi:10.1140/epjc/s10052-020-8299-6
abstract + abstract -

For direct CP-violation in K →π π decays, the usual isospin-breaking effects at the percent level are amplified by the dynamics behind the Δ I =1 /2 rule and conventionally encoded in ΩIB parameters. The updated prediction ΩIB(8 )=(15.9 ±8.2 ) ×10-2 of the Chiral Perturbation Theory for the strong isospin-breaking due to π38 mixing confirms such a tendency but is quite sensitive to the theoretical input value of the low-energy constant corresponding to the flavour-singlet η0 exchange contribution in this truncated octet scheme. We rather exploit the phenomenological η80 mixing as a probe for the non-negligible flavour-singlet component of the physical η pole to find ΩIB(9 )=(35 ±7 ) ×10-2 in a complete nonet scheme. A large central value in the nonet scheme is thus substituted for a large uncertainty in the octet one. Including the experimental π+0 mass difference as the dominant electromagnetic isospin-breaking, we obtain for the effective parameter entering the ratio ɛ'/ɛ an improved result Ω^eff(9 )=(29 ±7 ) ×10-2 to be compared with Ω^eff(8 )=(17 ±9 ) ×10-2 used in recent analyses of ɛ'/ɛ . Accordingly, we get a reduction from (ɛ'/ɛ)SM(8 )=(17.4 ±6.1 ) ×10-4 to (ɛ'/ɛ)SM(9 )=(13.9 ±5.2 ) ×10 -4 and thereby an effective suppression of (ɛ') SM by isospin-breaking corrections as large as 40 % relative to the recent RBC-UKQCD value.

(156)$\overline {MS}$ renormalization of $S$-wave quarkonium wavefunctions at the origin
  • Hee Sok Chung
abstract + abstract -

We compute S-wave quarkonium wavefunctions at the origin in the $ \overline{\mathrm{MS}} $ scheme based on nonrelativistic effective field theories. We include the effects of nonperturbative long-distance behaviors of the potentials, while we determine the short-distance behaviors of the potentials in perturbative QCD. We obtain $ \overline{\mathrm{MS}} $-renormalized quarkonium wavefunctions at the origin that have the correct scale dependences that are expected from perturbative QCD, so that the scale dependences cancel in physical quantities. Based on the calculation of the wavefunctions at the origin, we make model-independent predictions of decay constants and electromagnetic decay rates of S-wave charmonia and bottomonia, and compare them with measurements. We find that the poor convergence of perturbative QCD corrections are substantially improved when we include corrections to the wavefunctions at the origin in the calculation of decay constants and decay rates.

(155)Thermal Habitat for RNA Amplification and Accumulation
  • Annalena Salditt,
  • Lorenz M. R. Keil,
  • David P. Horning,
  • Christof B. Mast,
  • Gerald F. Joyce
  • +1
Physical Review Letters (07/2020) doi:10.1103/PhysRevLett.125.048104
abstract + abstract -

The RNA world scenario posits replication by RNA polymerases. On early Earth, a geophysical setting is required to separate hybridized strands after their replication and to localize them against diffusion. We present a pointed heat source that drives exponential, RNA-catalyzed amplification of short RNA with high efficiency in a confined chamber. While shorter strands were periodically melted by laminar convection, the temperature gradient caused aggregated polymerase molecules to accumulate, protecting them from degradation in hot regions of the chamber. These findings demonstrate a size-selective pathway for autonomous RNA-based replication in natural nonequilibrium conditions.

(154)Effective field theory for double heavy baryons at strong coupling
  • Joan Soto,
  • Jaume Tarrús Castellà
Physical Review D (07/2020) doi:10.1103/PhysRevD.102.014013
abstract + abstract -

We present an effective field theory for doubly heavy baryons that goes beyond the compact heavy diquark approximation. The heavy quark distance r is only restricted to mQ≫1 /r ≫Ebin , where mQ is the mass of the heavy quark and Ebin the typical binding energy. This means that the size of the heavy diquark can be as large as the typical size of a light hadron. We start from nonrelativistic QCD, and build the effective field theory at next-to-leading order in the 1 /mQ expansion. At leading order the effective field theory reduces to the Born-Oppenheimer approximation. The Born-Oppenheimer potentials are obtained from available lattice QCD data. The spectrum for double charm baryons below threshold is compatible with most of the lattice QCD results. We present for the first time the full spin averaged double bottom baryon spectrum below threshold based on QCD. We also present model-independent formulas for the spin splittings.

(153)Differential cross sections for neutron-proton scattering in the region of the d<SUP>*</SUP>(2380 ) dibaryon resonance
  • P. Adlarson,
  • W. Augustyniak,
  • W. Bardan,
  • M. Bashkanov,
  • F. S. Bergmann
  • +103
  • M. Berłowski,
  • H. Bhatt,
  • M. Büscher,
  • H. Calén,
  • I. Ciepał,
  • H. Clement,
  • D. Coderre,
  • E. Czerwiński,
  • K. Demmich,
  • E. Doroshkevich,
  • R. Engels,
  • A. Erven,
  • W. Erven,
  • W. Eyrich,
  • P. Fedorets,
  • K. Föhl,
  • K. Fransson,
  • F. Goldenbaum,
  • P. Goslawski,
  • A. Goswami,
  • K. Grigoryev,
  • C. -O. Gullström,
  • F. Hauenstein,
  • L. Heijkenskjöld,
  • V. Hejny,
  • M. Hodana,
  • B. Höistad,
  • N. Hüsken,
  • A. Jany,
  • B. R. Jany,
  • T. Johansson,
  • B. Kamys,
  • G. Kemmerling,
  • F. A. Khan,
  • A. Khoukaz,
  • D. A. Kirillov,
  • S. Kistryn,
  • H. Kleines,
  • B. Kłos,
  • M. Krapp,
  • W. Krzemień,
  • P. Kulessa,
  • A. Kupść,
  • K. Lalwani,
  • D. Lersch,
  • B. Lorentz,
  • A. Magiera,
  • R. Maier,
  • P. Marciniewski,
  • B. Mariański,
  • M. Mikirtychiants,
  • H. -P. Morsch,
  • P. Moskal,
  • H. Ohm,
  • I. Ozerianska,
  • E. Perez del Rio,
  • N. M. Piskunov,
  • P. Podkopał,
  • D. Prasuhn,
  • A. Pricking,
  • D. Pszczel,
  • K. Pysz,
  • A. Pyszniak,
  • C. F. Redmer,
  • J. Ritman,
  • A. Roy,
  • Z. Rudy,
  • S. Sawant,
  • S. Schadmand,
  • T. Sefzick,
  • V. Serdyuk,
  • R. Siudak,
  • T. Skorodko,
  • M. Skurzok,
  • J. Smyrski,
  • V. Sopov,
  • R. Stassen,
  • J. Stepaniak,
  • E. Stephan,
  • G. Sterzenbach,
  • H. Stockhorst,
  • H. Ströher,
  • A. Szczurek,
  • A. Täschner,
  • A. Trzciński,
  • R. Varma,
  • M. Wolke,
  • A. Wrońska,
  • P. Wüstner,
  • P. Wurm,
  • A. Yamamoto,
  • L. Yurev,
  • J. Zabierowski,
  • M. J. Zieliński,
  • A. Zink,
  • J. Złomańczuk,
  • P. Żuprański,
  • M. Żurek,
  • R. L. Workman,
  • W. J. Briscoe,
  • I. I. Strakovsky,
  • A. Švarc,
  • WASA-at-COSY Collaboration
  • (less)
Physical Review C (07/2020) doi:10.1103/PhysRevC.102.015204
abstract + abstract -

Differential cross sections have been extracted from exclusive and kinematically complete high-statistics measurements of quasifree polarized n ⃗p scattering performed in the energy region of the d*(2380 ) dibaryon resonance covering the range of beam energies Tn=0.98 -1.29 GeV (√{s }=2.32 -2.44 GeV). The experiment was carried out with the WASA-at-COSY setup having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process d p →n p +pspectator . In this way the n p differential cross section σ (Θ ) was measured over a large angular range. The obtained angular distributions complement the corresponding analyzing power Ay(Θ ) measurements published previously. A SAID partial-wave analysis incorporating the new data strengthens the finding of a resonance pole in the coupled D33-G33 waves.

(152)Voronoi volume function: a new probe of cosmology and galaxy evolution
  • Aseem Paranjape,
  • Shadab Alam
Monthly Notices of the Royal Astronomical Society (07/2020) doi:10.1093/mnras/staa1379
abstract + abstract -

We study the Voronoi volume function (VVF) - the distribution of cell volumes (or inverse local number density) in the Voronoi tessellation of any set of cosmological tracers (galaxies/haloes). We show that the shape of the VVF of biased tracers responds sensitively to physical properties such as halo mass, large-scale environment, substructure, and redshift-space effects, making this a hitherto unexplored probe of both primordial cosmology and galaxy evolution. Using convenient summary statistics - the width, median, and a low percentile of the VVF as functions of average tracer number density - we explore these effects for tracer populations in a suite of N-body simulations of a range of dark matter models. Our summary statistics sensitively probe primordial features such as small-scale oscillations in the initial matter power spectrum (as arise in models involving collisional effects in the dark sector), while being largely insensitive to a truncation of initial power (as in warm dark matter models). For vanilla cold dark matter (CDM) cosmologies, the summary statistics display strong evolution and redshift-space effects, and are also sensitive to cosmological parameter values for realistic tracer samples. Comparing the VVF of galaxies in the Galaxies & Mass Assembly (GAMA) survey with that of abundance-matched CDM (sub)haloes tentatively reveals environmental effects in GAMA beyond halo mass (modulo unmodelled satellite properties). Our exploratory analysis thus paves the way for using the VVF as a new probe of galaxy evolution physics as well as the nature of dark matter and dark energy.

(151)Gravitational decoherence of dark matter
  • Itamar Allali,
  • Mark P. Hertzberg
Journal of Cosmology and Astroparticle Physics (07/2020) doi:10.1088/1475-7516/2020/07/056
abstract + abstract -

Decoherence describes the tendency of quantum sub-systems to dynamically lose their quantum character. This happens when the quantum sub-system of interest interacts and becomes entangled with an environment that is traced out. For ordinary macroscopic systems, electromagnetic and other interactions cause rapid decoherence. However, dark matter (DM) may have the unique possibility of exhibiting naturally prolonged macroscopic quantum properties due to its weak coupling to its environment, particularly if it only interacts gravitationally. In this work, we compute the rate of decoherence for light DM in the galaxy, where a local density has its mass, size, and location in a quantum superposition. The decoherence is via the gravitational interaction of the DM overdensity with its environment, provided by ordinary matter. We focus on relatively robust configurations: DM perturbations that involve an overdensity followed by an underdensity, with no monopole, such that it is only observable at relatively close distances. We use non-relativistic scattering theory with a Newtonian potential generated by the overdensity to determine how a probe particle scatters off of it and thereby becomes entangled. As an application, we consider light scalar DM, including axions. In the galactic halo, we use diffuse hydrogen as the environment, while near the earth, we use air as the environment. For an overdensity whose size is the typical DM de Broglie wavelength, we find that the decoherence rate in the halo is higher than the present Hubble rate for DM masses ma lesssim 5 × 10-7 eV and in earth based experiments it is higher than the classical field coherence rate for ma lesssim 10-6 eV . When spreading of the states occurs, the rates can become much faster, as we quantify. Also, we establish that DM BECs decohere very rapidly and so are very well described by classical field theory.

(150)Microwave cavity searches for low-frequency axion dark matter
  • Robert Lasenby
Physical Review D (07/2020) doi:10.1103/PhysRevD.102.015008
abstract + abstract -

For low-mass (frequency ≪GHz ) axions, dark matter detection experiments searching for an axion-photon-photon coupling generally have suppressed sensitivity, if they use a static background magnetic field. This geometric suppression can be alleviated by using a high-frequency oscillating background field. Here, we present a high-level sketch of such an experiment, using superconducting cavities at ∼GHz frequencies. We discuss the physical limits on signal power arising from cavity properties, and point out cavity geometries that could circumvent some of these limitations. We also consider how backgrounds, including vibrational noise and drive signal leakage, might impact sensitivity. While practical microwave field strengths are significantly below attainable static magnetic fields, the lack of geometric suppression, and higher quality factors, may allow superconducting cavity experiments to be competitive in some regimes.

(149)Axion dark matter detection by superconducting resonant frequency conversion
  • Asher Berlin,
  • Raffaele Tito D'Agnolo,
  • Sebastian A. R. Ellis,
  • Christopher Nantista,
  • Jeffrey Neilson
  • +4
  • Philip Schuster,
  • Sami Tantawi,
  • Natalia Toro,
  • Kevin Zhou
  • (less)
Journal of High Energy Physics (07/2020) doi:10.1007/JHEP07(2020)088
abstract + abstract -

We propose an approach to search for axion dark matter with a specially designed superconducting radio frequency cavity, targeting axions with masses ma ≲ 10-6 eV. Our approach exploits axion-induced transitions between nearly degenerate resonant modes of frequency ∼ GHz. A scan over axion mass is achieved by varying the frequency splitting between the two modes. Compared to traditional approaches, this allows for parametrically enhanced signal power for axions lighter than a GHz. The projected sensitivity covers unexplored parameter space for QCD axion dark matter for 10-8 eV ≲ ma ≲ 10-6 eV and axion-like particle dark matter as light as ma∼ 10-14 eV.

(148)Axial-vector and pseudoscalar mesons in the hadronic light-by-light contribution to the muon (g -2 )
  • Luigi Cappiello,
  • Oscar Catà,
  • Giancarlo D'Ambrosio,
  • David Greynat,
  • Abhishek Iyer
Physical Review D (07/2020) doi:10.1103/PhysRevD.102.016009
abstract + abstract -

Despite recent developments, there are a number of conceptual issues on the hadronic light-by-light (HLbL) contribution to the muon (g -2 ) which remain unresolved. One of the most controversial ones is the precise way in which short-distance constraints get saturated by resonance exchange, particularly in the so-called Melnikov-Vainshtein limit. In this paper we address this and related issues from a novel perspective, employing a warped five-dimensional model as a tool to generate a consistent realization of QCD in the large-Nc limit. This approach differs from previous ones in that we can work at the level of an effective action, which guarantees that unitarity is preserved and the chiral anomaly is consistently implemented at the hadronic level. We use the model to evaluate the inclusive contribution of Goldstone modes and axial-vector mesons to the HLbL. We find that both anomaly matching and the Melnikov-Vainshtein constraint cannot be fulfilled with a finite number of resonances (including the pion) and instead require an infinite number of axial-vector states. Our numbers for the HLbL point at a non-negligible role of axial-vector mesons, which is closely linked to a correct implementation of QCD short-distance constraints.

(147)Nonrelativistic effective field theory for heavy exotic hadrons
  • Joan Soto,
  • Jaume Tarrús Castellà
Physical Review D (07/2020) doi:10.1103/PhysRevD.102.014012
abstract + abstract -

We propose an effective field theory to describe hadrons with two heavy quarks without any assumption on the typical distance between the heavy quarks with respect to the typical hadronic scale. The construction is based on nonrelativistic QCD and inspired in the strong coupling regime of potential nonrelativistic QCD. We construct the effective theory at leading and next-to-leading order in the inverse heavy quark mass expansion for arbitrary quantum numbers of the light degrees of freedom. Hence our results hold for hybrids, tetraquarks, double heavy baryons and pentaquarks, for which we also present the corresponding operators at a nonrelativistic level. At leading order, the effective theory enjoys heavy quark spin symmetry and corresponds to the Born-Oppenheimer approximation. At next-to-leading order, spin and velocity-dependent terms arise, which produce splittings in the heavy quark spin symmetry multiplets. A concrete application to double heavy baryons is presented in an accompanying paper.

(146)Ns 1987A in SN 1987A
  • Dany Page,
  • Mikhail V. Beznogov,
  • Iván Garibay,
  • James M. Lattimer,
  • Madappa Prakash
  • +1
The Astrophysical Journal (07/2020) doi:10.3847/1538-4357/ab93c2
abstract + abstract -

The possible detection of a compact object in the remnant of SN 1987A presents an unprecedented opportunity to follow its early evolution. The suspected detection stems from an excess of infrared emission from a dust blob near the compact object's predicted position. The infrared excess could be due to the decay of isotopes like 44Ti, accretion luminosity from a neutron star or black hole, magnetospheric emission or a wind originating from the spin down of a pulsar, or to thermal emission from an embedded, cooling neutron star (NS 1987A). It is shown that the last possibility is the most plausible as the other explanations are disfavored by other observations and/or require fine-tuning of parameters. Not only are there indications that the dust blob overlaps the predicted location of a kicked compact remnant, but its excess luminosity also matches the expected thermal power of a 30 yr old neutron star. Furthermore, models of cooling neutron stars within the minimal cooling paradigm readily fit both NS 1987A and Cas A, the next-youngest known neutron star. If correct, a long heat transport timescale in the crust and a large effective stellar temperature are favored, implying relatively limited crustal n-1S0 superfluidity and an envelope with a thick layer of light elements, respectively. If the locations do not overlap, then pulsar spin down or accretion might be more likely, but the pulsar's period and magnetic field or the accretion rate must be rather finely tuned. In this case, NS 1987A may have enhanced cooling and/or a heavy-element envelope.

(145)Merger rates in primordial black hole clusters without initial binaries
  • Valeriya Korol,
  • Ilya Mandel,
  • M. Coleman Miller,
  • Ross P. Church,
  • Melvyn B. Davies
Monthly Notices of the Royal Astronomical Society (07/2020) doi:10.1093/mnras/staa1644
abstract + abstract -

Primordial black holes formed through the collapse of cosmological density fluctuations have been hypothesized as contributors to the dark matter content of the Universe. At the same time, their mergers could contribute to the recently observed population of gravitational-wave sources. We investigate the scenario in which primordial black holes form binaries at late times in the Universe. Specifically, we re-examine the mergers of primordial black holes in small clusters of ∼30 objects in the absence of initial binaries. Binaries form dynamically through Newtonian gravitational interactions. These binaries act as heat sources for the cluster, increasing the cluster's velocity dispersion, which inhibits direct mergers through gravitational-wave two-body captures. Meanwhile, three-body encounters of tight binaries are too rare to tighten binaries sufficiently to allow them to merge through gravitational-wave emission. We conclude that in the absence of initial binaries, merger rates of primordial black holes in the considered scenario are at least an order of magnitude lower than previously suggested, which makes gravitational-wave detections of such sources improbable.

(144)Lyman α absorption beyond the disc of simulated spiral galaxies
  • Bernhard Röttgers,
  • Thorsten Naab,
  • Miha Cernetic,
  • Romeel Davé,
  • Guinevere Kauffmann
  • +2
  • Sanchayeeta Borthakur,
  • Horst Foidl
  • (less)
Monthly Notices of the Royal Astronomical Society (07/2020) doi:10.1093/mnras/staa1490
abstract + abstract -

We present an analysis of the origin and properties of the circumgalactic medium (CGM) in a suite of 11 cosmological zoom simulations resembling present-day spiral galaxies. On average the galaxies retain about 50 per cent of the cosmic fraction in baryons, almost equally divided into disc (interstellar medium) gas, cool CGM gas and warm-hot CGM gas. At radii smaller than 50 kpc the CGM is dominated by recycled warm-hot gas injected from the central galaxy, while at larger radii it is dominated by cool gas accreted on to the halo. The recycled gas typically accounts for one-third of the CGM mass. We introduce the novel publicly available analysis tool pygad to compute ion abundances and mock absorption spectra. For Lyman α absorption, we find good agreement of the simulated equivalent width (EW) distribution and observations out to large radii. Disc galaxies with quiescent assembly histories show significantly more absorption along the disc major axis. By comparing the EW and H I column densities, we find that CGM Lyman α absorbers are best represented by an effective line width b ≍ 50-70 km s-1 that increases mildly with halo mass, larger than typically assumed.

(143)Power meets precision to explore the symmetric Higgs portal
  • Christoph Englert,
  • Joerg Jaeckel,
  • Michael Spannowsky,
  • Panagiotis Stylianou
Physics Letters B (07/2020) doi:10.1016/j.physletb.2020.135526
abstract + abstract -

We perform a comprehensive study of collider aspects of a Higgs portal scenario that is protected by an unbroken Z2 symmetry. If the mass of the Higgs portal scalar is larger than half the Higgs mass, this scenario becomes very difficult to detect. We provide a detailed investigation of the model's parameter space based on analyses of the direct collider sensitivity at the LHC as well as at future lepton and hadron collider concepts and analyse the importance of these searches for this scenario in the context of expected precision Higgs and electroweak measurements. In particular we also consider the associated electroweak oblique corrections that we obtain in a first dedicated two-loop calculation for comparisons with the potential of, e.g., GigaZ. The currently available collider projections corroborate an FCC-hh 100 TeV as a very sensitive tool to search for such a weakly-coupled Higgs sector extension, driven by small statistical uncertainties over a large range of energy coverage. Crucially, however, this requires good theoretical control. Alternatively, Higgs signal-strength measurements at an optimal FCC-ee sensitivity level could yield comparable constraints.

(142)Muons in Supernovae: Implications for the Axion-Muon Coupling
  • Robert Bollig,
  • William DeRocco,
  • Peter W. Graham,
  • Hans-Thomas Janka
Physical Review Letters (07/2020) doi:10.1103/PhysRevLett.125.051104
abstract + abstract -

The high temperature and electron degeneracy attained during a supernova allow for the formation of a large muon abundance within the core of the resulting protoneutron star. If new pseudoscalar degrees of freedom have large couplings to the muon, they can be produced by this muon abundance and contribute to the cooling of the star. By generating the largest collection of supernova simulations with muons to date, we show that observations of the cooling rate of SN 1987A place strong constraints on the coupling of axionlike particles to muons, limiting the coupling to ga μ<10-8.1 GeV-1.

(141)Radio-emission of axion stars
  • D. G. Levkov,
  • A. G. Panin,
  • I. I. Tkachev
Physical Review D (07/2020) doi:10.1103/PhysRevD.102.023501
abstract + abstract -

We study parametric instability of compact axion dark matter structures decaying to radiophotons. Corresponding objects—Bose (axion) stars, their clusters, and clouds of diffuse axions—form abundantly in the postinflationary Peccei-Quinn scenario. We develop general description of parametric resonance incorporating finite-volume effects, backreaction, axion velocities, and their (in)coherence. With additional coarse graining, our formalism reproduces kinetic equation for virialized axions interacting with photons. We derive conditions for the parametric instability in each of the above objects, as well as in collapsing axion stars, evaluate photon resonance modes and their growth exponents. As a by-product, we calculate stimulated emission of Bose stars and diffuse axions, arguing that the former can give larger contribution into the radio background. In the case of QCD axions, the Bose stars glow and collapsing stars radioburst if the axion-photon coupling exceeds the original Kim-Shifman-Vainshtein-Zakharov value by 2 orders of magnitude. The latter constraint is alleviated for several nearby axion stars in resonance and absent for axionlike particles. Our results show that the parametric effect may reveal itself in observations, from fast radio bursts to excess radio background.

(140)First Simulations of Axion Minicluster Halos
  • Benedikt Eggemeier,
  • Javier Redondo,
  • Klaus Dolag,
  • Jens C. Niemeyer,
  • Alejandro Vaquero
Physical Review Letters (07/2020) doi:10.1103/PhysRevLett.125.041301
abstract + abstract -

We study the gravitational collapse of axion dark matter fluctuations in the postinflationary scenario, so-called axion miniclusters, with N -body simulations. Largely confirming theoretical expectations, overdensities begin to collapse in the radiation-dominated epoch and form an early distribution of miniclusters with masses up to 10-12 M . After matter-radiation equality, ongoing mergers give rise to a steep power-law distribution of minicluster halo masses. The density profiles of well-resolved halos are Navarro-Frenk-White-like to good approximation. The fraction of axion dark matter in these bound structures is ∼0.75 at redshift z =100 .

(139)Addressing R<SUB>D (*)</SUB> , R<SUB>K (*)</SUB> , muon g -2 and ANITA anomalies in a minimal R -parity violating supersymmetric framework
  • Wolfgang Altmannshofer,
  • P. S. Bhupal Dev,
  • Amarjit Soni,
  • Yicong Sui
Physical Review D (07/2020) doi:10.1103/PhysRevD.102.015031
abstract + abstract -

We analyze the recent hints of lepton flavor universality violation in both charged-current and neutral-current rare decays of B mesons in an R -parity-violating supersymmetric scenario. Motivated by simplicity and minimality, we had earlier postulated the third-generation superpartners to be the lightest (calling the scenario "RPV3") and explicitly showed that it preserves gauge coupling unification and of course has the usual attribute of naturally addressing the Higgs radiative stability. Here we show that both RD(*) and RK(*) flavor anomalies can be addressed in this RPV3 framework. Interestingly, this scenario may also be able to accommodate two other seemingly disparate anomalies, namely, the longstanding discrepancy in the muon (g -2 ), as well as the recent anomalous upgoing ultrahigh-energy Antarctic Impulsive Transient Antenna events. Based on symmetry arguments, we consider three different benchmark points for the relevant RPV3 couplings and carve out the regions of parameter space where all (or some) of these anomalies can be simultaneously explained. We find it remarkable that such overlap regions exist, given the plethora of precision low-energy and high-energy experimental constraints on the minimal model parameter space. The third-generation superpartners needed in this theoretical construction are all in the 1-10 TeV range, accessible at the LHC and/or next-generation hadron colliders. We also discuss some testable predictions for the lepton-flavor-violating decays of the tau lepton and B mesons for the current and future B -physics experiments, such as LHCb and Belle II. Complementary tests of the flavor anomalies in the high-pT regime in collider experiments such as the LHC are also discussed.

(138)The landscape of QCD axion models
  • Luca Di Luzio,
  • Maurizio Giannotti,
  • Enrico Nardi,
  • Luca Visinelli
Physics Reports (07/2020) doi:10.1016/j.physrep.2020.06.002
abstract + abstract -

We review the landscape of QCD axion models. Theoretical constructions that extend the window for the axion mass and couplings beyond conventional regions are highlighted and classified. Bounds from cosmology, astrophysics and experimental searches are reexamined and updated.

(137)Galaxy formation in the brane world I: overview and first results
  • César Hernández-Aguayo,
  • Christian Arnold,
  • Baojiu Li,
  • Carlton M. Baugh
Mon.Not.Roy.Astron.Soc. (06/2020) e-Print:2006.15467 doi:10.1093/mnras/stab694
abstract + abstract -

We carry out ‘full-physics’ hydrodynamical simulations of galaxy formation in the normal-branch Dvali–Gabadadze–Porrati (nDGP) braneworld model using a new modified version of the arepo code and the IllustrisTNG galaxy formation model. We simulate two nDGP models (N5 and N1) that represent, respectively, weak and moderate departures from general relativity (GR), in boxes of sizes |$62$| and |$25\, h^{-1}{\rm Mpc}$| using 2 × 512^3 dark matter particles and initial gas cells. This allows us to explore, for the first time, the impact of baryonic physics on galactic scales in braneworld models of modified gravity and to make predictions on the stellar content of dark matter haloes and galaxy evolution through cosmic time in these models. We find significant differences between the GR and nDGP models in the power spectra and correlation functions of gas, stars and dark matter of up to ∼25 per cent on large scales. Similar to their impact in the standard cosmological model (Λ cold dark matter), baryonic effects can have a significant influence over the clustering of the overall matter distribution, with a sign that depends on scale. Studying the degeneracy between modified gravity and galactic feedback in these models, we find that these two physical effects on matter clustering can be cleanly disentangled, allowing for a method to accurately predict the matter power spectrum with baryonic effects included, without having to run hydrodynamical simulations. Depending on the braneworld model, we find differences compared with GR of up to ∼15 per cent in galaxy properties such as the stellar-to-halo-mass ratio, galaxy stellar mass function, gas fraction, and star formation rate density. The amplitude of the fifth force is reduced by the presence of baryons in the very inner part of haloes, but this reduction quickly becomes negligible above ∼0.1 times the halo radius.

(136)Giant star-forming clumps?
  • R. J. Ivison,
  • J. Richard,
  • A. D. Biggs,
  • M. A. Zwaan,
  • E. Falgarone
  • +3
  • V. Arumugam,
  • P. P. van der Werf,
  • W. Rujopakarn
  • (less)
Monthly Notices of the Royal Astronomical Society (06/2020) doi:10.1093/mnrasl/slaa046
abstract + abstract -

With the spatial resolution of the Atacama Large Millimetre Array (ALMA), dusty galaxies in the distant Universe typically appear as single, compact blobs of dust emission, with a median half-light radius, ≍1 kpc. Occasionally, strong gravitational lensing by foreground galaxies or galaxy clusters has probed spatial scales 1-2 orders of magnitude smaller, often revealing late-stage mergers, sometimes with tantalizing hints of sub-structure. One lensed galaxy in particular, the Cosmic Eyelash at z = 2.3, has been cited extensively as an example of where the interstellar medium exhibits obvious, pronounced clumps, on a spatial scale of ≍100 pc. Seven orders of magnitude more luminous than giant molecular clouds in the local Universe, these features are presented as circumstantial evidence that the blue clumps observed in many z ∼ 2-3 galaxies are important sites of ongoing star formation, with significant masses of gas and stars. Here, we present data from ALMA which reveal that the dust continuum of the Cosmic Eyelash is in fact smooth and can be reproduced using two Sérsic profiles with effective radii, 1.2 and 4.4 kpc, with no evidence of significant star-forming clumps down to a spatial scale of ≍80 pc and a star formation rate of <3 M yr-1.

(135)The Birth Function for Black Holes and Neutron Stars in Close Binaries
  • S. E. Woosley,
  • Tuguldur Sukhbold,
  • H. -T. Janka
The Astrophysical Journal (06/2020) doi:10.3847/1538-4357/ab8cc1
abstract + abstract -

The mass function for black holes and neutron stars at birth is explored for mass-losing helium stars. These should resemble, more closely than similar studies of single hydrogen-rich stars, the results of evolution in close binary systems. The effects of varying the mass-loss rate and metallicity are calculated using a simple semi-analytic approach to stellar evolution that is tuned to reproduce detailed numerical calculations. Though the total fraction of black holes made in stellar collapse events varies considerably with metallicity, mass-loss rate, and mass cutoff, from 5% to 30%, the shapes of their birth functions are very similar for all reasonable variations in these quantities. Median neutron star masses are in the range 1.32-1.37 ${M}_{\odot }$ regardless of metallicity. The median black hole mass for solar metallicity is typically 8-9 ${M}_{\odot }$ if only initial helium cores below 40 ${M}_{\odot }$ (ZAMS mass less than 80 ${M}_{\odot }$ ) are counted, and 9-13 ${M}_{\odot }$, in most cases, if helium cores with initial masses up to 150 ${M}_{\odot }$ (ZAMS mass less than 300 ${M}_{\odot }$ ) contribute. As long as the mass-loss rate as a function of mass exhibits no strong nonlinearities, the black hole birth function from 15 to 35 ${M}_{\odot }$ has a slope that depends mostly on the initial mass function for main-sequence stars. These findings imply the possibility of constraining the initial mass function and the properties of mass loss in close binaries using ongoing measurements of gravitational-wave radiation. The expected rotation rates of the black holes are briefly discussed.

(134)The stellar mass Fundamental Plane: the virial relation and a very thin plane for slow rotators
  • M. Bernardi,
  • H. Domínguez Sánchez,
  • B. Margalef-Bentabol,
  • F. Nikakhtar,
  • R. K. Sheth
Monthly Notices of the Royal Astronomical Society (06/2020) doi:10.1093/mnras/staa1064
abstract + abstract -

Early-type galaxies - slow and fast rotating ellipticals (E-SRs and E-FRs) and S0s/lenticulars - define a Fundamental Plane (FP) in the space of half-light radius Re, enclosed surface brightness Ie, and velocity dispersion σe. Since Ie and σe are distance-independent measurements, the thickness of the FP is often expressed in terms of the accuracy with which Ie and σe can be used to estimate sizes Re. We show that: (1) The thickness of the FP depends strongly on morphology. If the sample only includes E-SRs, then the observed scatter in Re is ∼ 16 per cent, of which only ∼ 9 per cent is intrinsic. Removing galaxies with M* < 1011 M further reduces the observed scatter to ∼ 13 per cent (∼ 4 per cent intrinsic). The observed scatter increases to ∼ 25 per cent usually quoted in the literature if E-FRs and S0s are added. If the FP is defined using the eigenvectors of the covariance matrix of the observables, then the E-SRs again define an exceptionally thin FP, with intrinsic scatter of only 5 per cent orthogonal to the plane. (2) The structure within the FP is most easily understood as arising from the fact that Ie and σe are nearly independent, whereas the Re-Ie and Ree correlations are nearly equal and opposite. (3) If the coefficients of the FP differ from those associated with the virial theorem the plane is said to be 'tilted'. If we multiply Ie by the global stellar mass-to-light ratio M*/L and we account for non-homology across the population by using Sérsic photometry, then the resulting stellar mass FP is less tilted. Accounting self-consistently for M*/L gradients will change the tilt. The tilt we currently see suggests that the efficiency of turning baryons into stars increases and/or the dark matter fraction decreases as stellar surface brightness increases.

(133)Hot phase generation by supernovae in ISM simulations: resolution, chemistry, and thermal conduction
  • Ulrich P. Steinwandel,
  • Benjamin P. Moster,
  • Thorsten Naab,
  • Chia-Yu Hu,
  • Stefanie Walch
Monthly Notices of the Royal Astronomical Society (06/2020) doi:10.1093/mnras/staa821
abstract + abstract -

Supernovae (SNe) generate hot gas in the interstellar medium (ISM), help setting the ISM structure, and support the driving of outflows. It is important to resolve the hot gas generation for galaxy formation simulations at solar mass and sub-parsec resolution that realize individual SN explosions with ambient densities varying by several orders of magnitude in a realistic multiphase ISM. We test resolution requirements by simulating SN blast waves at three metallicities (Z = 0.01, 0.1, and 1 Z), six densities and their respective equilibrium chemical compositions (n = 0.001-100 cm-3), and four mass resolutions (0.1-100 M), in three dimensions. We include non-equilibrium cooling and chemistry, a homogeneous interstellar radiation field, and shielding with a modern pressure-energy smoothed particle hydrodynamics method including isotropic thermal conduction and a meshless-finite-mass solver. We find stronger resolution requirements for chemistry and hot phase generation than for momentum generation. While at 10 M the radial momenta at the end of the Sedov phase start converging, the hot phase generation and chemistry require higher resolutions to represent the neutral-to-ionized hydrogen fraction at the end of the Sedov phase correctly. Thermal conduction typically reduces the hot phase by 0.2 dex and has little impact on the chemical composition. In general, our 1 and 0.1 M results agree well with previous numerical and analytic estimates. We conclude that for the thermal energy injection SN model presented here resolutions higher than 10 M are required to model the chemistry, momentum, and hot phase generation in the multiphase ISM.

(132)A formalism for magnon gravitational wave detectors
  • Asuka Ito,
  • Jiro Soda
European Physical Journal C (06/2020) doi:10.1140/epjc/s10052-020-8092-6
abstract + abstract -

In order to detect high frequency gravitational waves, we need a new detection method. In this paper, we develop a formalism for a gravitational wave detector using magnons in a cavity. Using Fermi normal coordinates and taking the non-relativistic limit, we obtain a Hamiltonian for magnons in gravitational wave backgrounds. Given the Hamiltonian, we show how to use the magnons for detecting high frequency gravitational waves. Furthermore, as a demonstration of the magnon gravitational wave detector, we give upper limits on GHz gravitational waves by utilizing known results of magnon experiments for an axion dark matter search.

(131)New high-sensitivity searches for neutrons converting into antineutrons and/or sterile neutrons at the HIBEAM/NNBAR experiment at the European Spallation Source
  • A. Addazi,
  • K. Anderson,
  • S. Ansellb,
  • K.S. Babua,
  • J. Cedercäll
  • +110
  • D.D. DiJulio,
  • S. Gardiner,
  • P. Geltenbort,
  • P. Golubev,
  • A. Holley,
  • G. Ichikawa,
  • T.M. Ito,
  • Z. Kokai,
  • B. Kerbikov,
  • J.L. Barrow,
  • D.V. Baxter,
  • P.M. Bentley,
  • Z. Berezhiani,
  • R. Bevilacqua,
  • C. Bohmb,
  • G. Brooijmans,
  • L.J. Broussard,
  • R. Biondi,
  • P.S. B. Dev,
  • C. Crawford,
  • A.D. Dolgov,
  • K. Dunne,
  • P. Fierlinger,
  • M.R. Fitzsimmons,
  • A. Fomin,
  • M.J. Frost,
  • S. Gardner,
  • A. Galindo-Uribarri,
  • E. Golubeva,
  • S. Girmohanta,
  • G.L. Greene,
  • T. Greenshaw,
  • V. Gudkov,
  • R. Hall-Wilton,
  • L. Heilbronn,
  • J. Herrero-Garcia,
  • E. Iverson,
  • T. Johansson,
  • L. Jönsson,
  • Y-J. Jwa,
  • Y. Kamyshkov,
  • K. Kanaki,
  • E. Kearns,
  • M. Kitaguchi,
  • T. Kittelmann,
  • E. Klinkby,
  • A. Kobakhidze,
  • L.W. Koerner,
  • B. Kopeliovich,
  • A. Kozela,
  • V. Kudryavtsev,
  • A. Kupsc,
  • Y.T. Lee,
  • M. Lindroos,
  • J. Makkinje,
  • J.I. Marquez,
  • R.N. Mohapatra,
  • B. Meirose,
  • T.M. Miller,
  • D. Milstead,
  • T. Morishima,
  • G. Muhrer,
  • H.P. Mumm,
  • K. Nagamoto,
  • A. Nepomuceno,
  • F. Nesti,
  • V.V. Nesvizhevsky,
  • T. Nilsson,
  • A. Oskarsson,
  • E. Paryev,
  • R.W.,
  • Jr. Pattie,
  • S. Penttilä,
  • H. Perrey,
  • Y.N. Pokotilovski,
  • I. Potashnikovab,
  • K. Ramic,
  • C. Redding,
  • J-M. Richard,
  • D. Ries,
  • E. Rinaldi,
  • R.N. Mohapatr,
  • N. Rossi,
  • A. Ruggles,
  • B. Rybolt,
  • V. Santoro,
  • U. Sarkar,
  • A. Saunders,
  • G. Senjanovic,
  • A.P. Serebrov,
  • H.M. Shimizu,
  • R. Shrock,
  • S. Silverstein,
  • D. Silvermyr,
  • W.M. Snow,
  • A. Takibayev,
  • L. Townsend,
  • I. Tkachev,
  • A. Tureanu,
  • L. Varriano,
  • A. Vainshtein,
  • J. de Vries,
  • R. Wagner,
  • R. Woracek,
  • Y. Yamagata,
  • S. Yiu,
  • A.R. Young,
  • L. Zanini,
  • Z. Zhang,
  • O. Zimmer
  • (less)
abstract + abstract -

The violation of baryon number, , is an essential ingredient for the preferential creation of matter over antimatter needed to account for the observed baryon asymmetry in the Universe. However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source to search for baryon number violation. The program will include high-sensitivity searches for processes that violate baryon number by one or two units: free neutron–antineutron oscillation () via mixing, neutron–antineutron oscillation via regeneration from a sterile neutron state (), and neutron disappearance (n → n′); the effective process of neutron regeneration () is also possible. The program can be used to discover and characterize mixing in the neutron, antineutron and sterile neutron sectors. The experiment addresses topical open questions such as the origins of baryogenesis and the nature of dark matter, and is sensitive to scales of new physics substantially in excess of those available at colliders. A goal of the program is to open a discovery window to neutron conversion probabilities (sensitivities) by up to three orders of magnitude compared with previous searches. The opportunity to make such a leap in sensitivity tests should not be squandered. The experiment pulls together a diverse international team of physicists from the particle (collider and low energy) and nuclear physics communities, while also including specialists in neutronics and magnetics.

(130)The anomalous magnetic moment of the muon in the Standard Model
  • T. Aoyama,
  • N. Asmussen,
  • M. Benayoun,
  • J. Bijnens,
  • T. Blum
  • +127
  • M. Bruno,
  • I. Caprini,
  • C.M. Carloni Calame,
  • M. Cè,
  • G. Colangelo,
  • F. Curciarello,
  • H. Czyż,
  • I. Danilkin,
  • M. Davier,
  • C.T.H. Davies,
  • M. Della Morte,
  • S.I. Eidelman,
  • A.X. El-Khadra,
  • A. Gérardin,
  • D. Giusti,
  • M. Golterman,
  • Steven Gottlieb,
  • V. Gülpers,
  • F. Hagelstein,
  • M. Hayakawa,
  • G. Herdoíza,
  • D.W. Hertzog,
  • A. Hoecker,
  • M. Hoferichter,
  • B.-L. Hoid,
  • R.J. Hudspith,
  • F. Ignatov,
  • T. Izubuchi,
  • F. Jegerlehner,
  • L. Jin,
  • A. Keshavarzi,
  • T. Kinoshita,
  • B. Kubis,
  • A. Kupich,
  • A. Kupść,
  • L. Laub,
  • C. Lehner,
  • L. Lellouch,
  • I. Logashenko,
  • B. Malaescu,
  • K. Maltman,
  • M.K. Marinković,
  • P. Masjuan,
  • A.S. Meyer,
  • H.B. Meyer,
  • T. Mibe,
  • K. Miura,
  • S.E. Müller,
  • M. Nio,
  • D. Nomura,
  • A. Nyffeler,
  • V. Pascalutsa,
  • M. Passera,
  • E. Perez del Rio,
  • S. Peris,
  • A. Portelli,
  • M. Procura,
  • C.F. Redmer,
  • B.L. Roberts,
  • P. Sánchez-Puertas,
  • S. Serednyakov,
  • B. Shwartz,
  • S. Simula,
  • D. Stöckinger,
  • H. Stöckinger-Kim,
  • P. Stoffer,
  • T. Teubner,
  • R. Van de Water,
  • M. Vanderhaeghen,
  • G. Venanzoni,
  • G. von Hippel,
  • H. Wittig,
  • Z. Zhang,
  • M.N. Achasov,
  • A. Bashir,
  • N. Cardoso,
  • B. Chakraborty,
  • E.-H. Chao,
  • J. Charles,
  • A. Crivellin,
  • O. Deineka,
  • A. Denig,
  • C. DeTar,
  • C.A. Dominguez,
  • A.E. Dorokhov,
  • V.P. Druzhinin,
  • G. Eichmann,
  • M. Fael,
  • C.S. Fischer,
  • E. Gámiz,
  • Z. Gelzer,
  • J.R. Green,
  • S. Guellati-Khelifa,
  • D. Hatton,
  • N. Hermansson-Truedsson,
  • S. Holz,
  • B. Hörz,
  • M. Knecht,
  • J. Koponen,
  • A.S. Kronfeld,
  • J. Laiho,
  • S. Leupold,
  • P.B. Mackenzie,
  • W.J. Marciano,
  • C. McNeile,
  • D. Mohler,
  • J. Monnard,
  • E.T. Neil,
  • A.V. Nesterenko,
  • K. Ottnad,
  • V. Pauk,
  • A.E. Radzhabov,
  • E. de Rafael,
  • K. Raya,
  • A. Risch,
  • A. Rodríguez-Sánchez,
  • P. Roig,
  • T. San José,
  • E.P. Solodov,
  • R. Sugar,
  • K.Yu. Todyshev,
  • A. Vainshtein,
  • A. Vaquero Avilés-Casco,
  • E. Weil,
  • J. Wilhelm,
  • R. Williams,
  • A.S. Zhevlakov
  • (less)
abstract + abstract -

We review the present status of the Standard Model calculation of the anomalous magnetic moment of the muon. This is performed in a perturbative expansion in the fine-structure constant α and is broken down into pure QED, electroweak, and hadronic contributions. The pure QED contribution is by far the largest and has been evaluated up to and including O(α5) with negligible numerical uncertainty. The electroweak contribution is suppressed by (mμ∕MW)2 and only shows up at the level of the seventh significant digit. It has been evaluated up to two loops and is known to better than one percent. Hadronic contributions are the most difficult to calculate and are responsible for almost all of the theoretical uncertainty. The leading hadronic contribution appears at O(α2) and is due to hadronic vacuum polarization, whereas at O(α3) the hadronic light-by-light scattering contribution appears. Given the low characteristic scale of this observable, these contributions have to be calculated with nonperturbative methods, in particular, dispersion relations and the lattice approach to QCD. The largest part of this review is dedicated to a detailed account of recent efforts to improve the calculation of these two contributions with either a data-driven, dispersive approach, or a first-principle, lattice-QCD approach. The final result reads aμSM=116591810(43)×10−11 and is smaller than the Brookhaven measurement by 3.7 σ . The experimental uncertainty will soon be reduced by up to a factor four by the new experiment currently running at Fermilab, and also by the future J-PARC experiment. This and the prospects to further reduce the theoretical uncertainty in the near future – which are also discussed here – make this quantity one of the most promising places to look for evidence of new physics.

(129)Addendum to "Global constraints on absolute neutrino masses and their ordering"
  • Francesco Capozzi,
  • Eleonora Di Valentino,
  • Eligio Lisi,
  • Antonio Marrone,
  • Alessandro Melchiorri
  • +1
Physical Review D (06/2020) doi:10.1103/PhysRevD.101.116013
abstract + abstract -

We revisit our previous work [Capozzi et al., Phys. Rev. D 95, 096014 (2017), 10.1103/PhysRevD.95.096014] where neutrino oscillation and nonoscillation data were analyzed in the standard framework with three neutrino families, in order to constrain their absolute masses and to probe their ordering (either normal, NO, or inverted, IO). We include updated oscillation results to discuss best fits and allowed ranges for the two squared mass differences δ m2 and Δ m2, the three mixing angles θ12, θ23, and θ13, as well as constraints on the C P -violating phase δ , plus significant indications in favor of NO vs IO at the level of Δ χ2=10.0 . We then consider nonoscillation data from beta decay, from neutrinoless double beta decay (if neutrinos are Majorana), and from various cosmological input variants (in the data or the model) leading to results dubbed as default, aggressive, and conservative. In the default option, we obtain from nonoscillation data an extra contribution Δ χ2≃2.2 in favor of NO, and an upper bound on the sum of neutrino masses Σ <0.15 eV at 2 σ ; both results—dominated by cosmology—can be strengthened or weakened by using more aggressive or conservative options, respectively. Taking into account such variations, we find that the combination of all (oscillation and nonoscillation) neutrino data favors NO at the level of 3.2 -3.7 σ , and that Σ is constrained at the 2 σ level within Σ <0.12 - 0.69 eV . The upper edge of this allowed range corresponds to an effective β -decay neutrino mass mβ≃Σ /3 ≃0.23 eV , at the sensitivity frontier of the KATRIN experiment.

(128)Neutrino emission characteristics of black hole formation in three-dimensional simulations of stellar collapse
  • Laurie Walk,
  • Irene Tamborra,
  • Hans-Thomas Janka,
  • Alexander Summa,
  • Daniel Kresse
Physical Review D (06/2020) doi:10.1103/PhysRevD.101.123013
abstract + abstract -

Neutrinos are unique probes of core-collapse supernova dynamics, especially in the case of black hole (BH-)forming stellar collapses, where the electromagnetic emission may be faint or absent. By investigating two three-dimensional hydrodynamical simulations of BH-forming stellar collapses of mass 40 M and 75 M, we identify the physical processes preceding BH formation through neutrinos and forecast the neutrino signal expected in the existing IceCube and Super-Kamiokande detectors, as well as in the future generation DUNE facility. Prior to the abrupt termination of the neutrino signal corresponding to BH formation, both models develop episodes of strong and long-lasting activity by the spiral standing accretion shock instability (SASI). We find that the spiral SASI peak in the Fourier power spectrum of the neutrino event rate will be distinguishable at 3 σ above the detector noise for distances up to ∼O (30 ) kpc in the most optimistic scenario, with IceCube having the highest sensitivity. Interestingly, given the long duration of the spiral SASI episodes, the spectrograms of the expected neutrino event rate carry clear signs of the evolution of the spiral SASI frequency as a function of time, as the shock radius and postshock fluid velocity evolve. Because of the high accretion luminosity and its large-amplitude SASI-induced modulations, any contribution from asymmetric (dipolar or quadrupolar) neutrino emission associated with the lepton emission self-sustained asymmetry is far subdominant in the neutrino signal.

(127)Gauge Theory of Weak Decays
  • Andrzej J. Buras
Book (06/2020) doi:10.1017/9781139524100
abstract + abstract -

This is the first advanced, systematic and comprehensive look at weak decays in the framework of gauge theories. Included is a large spectrum of topics, both theoretical and experimental. In addition to explicit advanced calculations of Feynman diagrams and the study of renormalization group strong interaction effects in weak decays, the book is devoted to the Standard Model Effective Theory, dominating present phenomenology in this field, and to new physics models with the goal of searching for new particles and interactions through quantum fluctuations. This book will benefit theorists, experimental researchers, and Ph.D. students working on flavour physics and weak decays as well as physicists interested in physics beyond the Standard Model. In its concern for the search for new phenomena at short distance scales through the interplay between theory and experiment, this book constitutes a travel guide to physics far beyond the scales explored by the Large Hadron Collider at CERN.

(126)Gradient flow step-scaling function for SU(3) with ten fundamental flavors
  • A. Hasenfratz,
  • C. Rebbi,
  • O. Witzel
Physical Review D (06/2020) doi:10.1103/PhysRevD.101.114508
abstract + abstract -

We calculate the step-scaling function, the lattice analog of the renormalization group β -function, for an SU(3) gauge theory with ten fundamental flavors. We present a detailed analysis including the study of systematic effects of our extensive data set generated with ten dynamical flavors using the Symanzik gauge action and three times stout smeared Möbius domain wall fermions. Using up to 324 volumes, we calculate renormalized couplings for different gradient flow schemes and determine the step-scaling β function for a scale change s =2 on up to five different lattice volume pairs. In an accompanying paper we discuss that gradient flow can promote lattice dislocations to instantonlike objects, introducing nonperturbative lattice artifacts to the step-scaling function. Motivated by the observation that Wilson flow sufficiently suppresses these artifacts, we choose Wilson flow with the Symanzik operator as our preferred analysis. We study systematic effects by calculating the step-scaling function based on alternative flows (Zeuthen or Symanzik), alternative operators (Wilson plaquette, clover), and also explore the effects of the perturbative tree-level improvement. Further we investigate the effects due to the finite value of Ls.

(125)Stellar property statistics of massive haloes from cosmological hydrodynamics simulations: common kernel shapes
  • Dhayaa Anbajagane,
  • August E. Evrard,
  • Arya Farahi,
  • David J. Barnes,
  • Klaus Dolag
  • +3
  • Ian G. McCarthy,
  • Dylan Nelson,
  • Annalisa Pillepich
  • (less)
Monthly Notices of the Royal Astronomical Society (06/2020) doi:10.1093/mnras/staa1147
abstract + abstract -

We study stellar property statistics, including satellite galaxy occupation, of haloes in three cosmological hydrodynamics simulations: BAHAMAS + MACSIS, IllustrisTNG, and Magneticum Pathfinder. Applying localized linear regression, we extract halo mass-conditioned normalizations, slopes, and intrinsic covariance for (i) Nsat, the number of stellar mass-thresholded satellite galaxies within radius R200c of the halo; (ii) M⋆,tot, the total stellar mass within that radius, and (iii) M⋆,BCG, the gravitationally bound stellar mass of the central galaxy within a 100 kpc radius. The parameters show differences across the simulations, in part from numerical resolution, but there is qualitative agreement for the Nsat - M⋆,BCG correlation. Marginalizing over Mhalo, we find the Nsat kernel, p(ln Nsat | Mhalo,z) to be consistently skewed left in all three simulations, with skewness parameter γ = -0.91 ± 0.02, while the M⋆,tot kernel shape is closer to lognormal. The highest resolution simulations find γ ≃ -0.8 for the z = 0 shape of the M⋆,BCG kernel. We provide a Gaussian mixture fit to the low-redshift Nsat kernel as well as local linear regression parameters tabulated for Mhalo > 1013.5 M⊙ in all simulations.

(124)On Spin dependence of the Fundamental Plane of black hole activity
  • Caner Ünal,
  • Abraham Loeb
Monthly Notices of the Royal Astronomical Society (06/2020) doi:10.1093/mnras/staa1119
abstract + abstract -

The Fundamental Plane (FP) of black hole (BH) activity in galactic nuclei relates X-ray and radio luminosities to BH mass and accretion rate. However, there is a large scatter exhibited by the data, which motivated us for a new variable. We add BH spin as a new variable and estimate the spin dependence of the jet power and disc luminosity in terms of radio and X-ray luminosities. We assume the Blandford-Znajek process as the main source of the outflow, and find that the jet power depends on BH spin stronger than quadratically at moderate and large spin values. We perform a statistical analysis for 10 active galactic nuclei (AGNs) which have sub-Eddington accretion rates and whose spin values are measured independently via the reflection or continuum-fitting methods, and find that the spin-dependent relation describes the data significantly better. This analysis, if supported with more data, could imply not only the spin dependence of the FP relation, but also the Blandford-Znajek process in AGN jets.

(123)Revisiting longitudinal plasmon-axion conversion in external magnetic fields
  • Andrea Caputo,
  • Alexander J. Millar,
  • Edoardo Vitagliano
Physical Review D (06/2020) doi:10.1103/PhysRevD.101.123004
abstract + abstract -

In the presence of an external magnetic field, the axion and the photon mix. In particular, the dispersion relation of a longitudinal plasmon always crosses the dispersion relation of the axion (for small axion masses), thus leading to a resonant conversion. Using thermal field theory, we concisely derive the axion emission rate, applying it to astrophysical and laboratory scenarios. For the Sun, depending on the magnetic field profile, plasmon-axion conversion can dominate over Primakoff production at low energies (≲200 eV ). This both provides a new axion source for future helioscopes and, in the event of discovery, would probe the magnetic field structure of the Sun. In the case of white dwarfs (WDs), plasmon-axion conversion provides a pure photon coupling probe of the axion, which may contribute significantly for low-mass WDs. Finally, we rederive and confirm the axion absorption rate of the recently proposed plasma haloscopes.

(122)Bottomonium spectrum with a Dirac potential model in the momentum space
  • David Molina,
  • Maurizio De Sanctis,
  • César Fernández-Ramírez,
  • Elena Santopinto
European Physical Journal C (06/2020) doi:10.1140/epjc/s10052-020-8099-z
abstract + abstract -

We study the bottomonium spectrum using a relativistic potential model in the momentum space. This model is based on a complete one gluon exchange interaction with a momentum dependent screening factor to account for the effects due to virtual pair creation that appear close to the decay thresholds. The overall model does not make use of nonrelativistic approximations. We fit well established bottomonium states below the open bottom threshold and predict the rest of the spectrum up to ≈11200 MeV and JPC=3-- . Uncertainties are treated rigorously and propagated in full to the parameters of the model using a Monte Carlo to identify if which deviations from experimental data can be absorbed into the statistical uncertainties of the models and which can be related to physics beyond the b b ¯ picture, guiding future research. We get a good description of the spectrum, in particular the Belle measurement of the ηb(2 S ) state and the Υ (10860 ) and χb(3 P ) resonances.

(121)Effects of gravitational Chern-Simons during Axion-SU(2) inflation
  • Leila Mirzagholi,
  • Eiichiro Komatsu,
  • Kaloian D. Lozanov,
  • Yuki Watanabe
Journal of Cosmology and Astroparticle Physics (06/2020) doi:10.1088/1475-7516/2020/06/024
abstract + abstract -

In this paper we examine the viability of inflation models with a spectator axion field coupled to both gravitational and SU(2) gauge fields via Chern-Simons couplings. Requiring phenomenological success of the axion-SU(2) sector constrains the coupling strength of the gravitational Chern-Simons term. We find that the impact of this term on the production and propagation of gravitational waves can be as large as fifty percent enhancement for the helicity that is not sourced by the gauge field, if the cut-off scale is as low as Λ = 20H. The effect becomes smaller for a larger value of Λ, while the impact on the helicity sourced by the gauge field is negligible regardless of Λ.

(120)More accurate simulations with separate initial conditions for baryons and dark matter
  • Simeon Bird,
  • Yu Feng,
  • Christian Pedersen,
  • Andreu Font-Ribera
Journal of Cosmology and Astroparticle Physics (06/2020) doi:10.1088/1475-7516/2020/06/002
abstract + abstract -

We revisit techniques for performing cosmological simulations with both baryons and cold dark matter when each fluid has different initial conditions, as is the case at the end of the radiation era. Most simulations do not reproduce the linear prediction for the difference between the cold dark matter and baryon perturbations. We show that this is due to the common use of offset regular grids when setting up the particle initial conditions. The desired linear evolution can be obtained without any loss of simulation resolution by using a Lagrangian glass for the baryon particles. We further show that the difference between cold dark matter and baryons may affect predictions for the Lyman-α forest flux power spectrum at the 5% level, potentially impacting current cosmological constraints.

(119)Functional methods for Heavy Quark Effective Theory
  • Timothy Cohen,
  • Marat Freytsis,
  • Xiaochuan Lu
Journal of High Energy Physics (06/2020) doi:10.1007/JHEP06(2020)164
abstract + abstract -

We use functional methods to compute one-loop effects in Heavy Quark Effective Theory. The covariant derivative expansion technique facilitates the efficient extraction of matching coefficients and renormalization group evolution equations. This paper pro- vides the first demonstration that such calculations can be performed through the algebraic evaluation of the path integral for the class of effective field theories that are (i) constructed using a non-trivial one-to-many mode decomposition of the UV theory, and (ii) valid for non-relativistic kinematics. We discuss the interplay between operators that appear at intermediate steps and the constraints imposed by the residual Lorentz symmetry that is encoded as reparameterization invariance within the effective description. The tools presented here provide a systematic approach for computing corrections to higher order in the heavy mass expansion; precision applications include predictions for experimental data and connections to theoretical tests via lattice QCD. A set of pedagogical appendices comprehensively reviews modern approaches to performing functional calculations algebraically, and derives contributions from a term with open covariant derivatives for the first time.

(118)Building a digital twin of a luminous red galaxy spectroscopic survey: galaxy properties and clustering covariance
  • César Hernández-Aguayo,
  • Francisco Prada,
  • Carlton M. Baugh,
  • Anatoly Klypin
Mon.Not.Roy.Astron.Soc. (05/2020) e-Print:2006.00612 doi:10.1093/mnras/stab434
abstract + abstract -

Upcoming surveys will use a variety of galaxy selections to map the large-scale structure of the Universe. It is important to make accurate predictions for the properties and clustering of such galaxies, including the errors on these statistics. Here, we describe a novel technique which uses the semi-analytical model of galaxy formation galform, embedded in the high-resolution N-body Planck-Millennium simulation, to populate a thousand halo catalogues generated using the Parallel-PM N-body glam code. Our hybrid scheme allows us to make clustering predictions on scales that cannot be modelled in the original N-body simulation. We focus on luminous red galaxies (LRGs) selected in the redshift range z = 0.6 − 1 from the galform output using similar colour-magnitude cuts in the r, z, and W1 bands to those that will be applied in the Dark Energy Spectroscopic Instrument (DESI) survey, and call this illustrative sample ‘DESI-like’ LRGs. We find that the LRG-halo connection is non-trivial, leading to the prediction of a non-standard halo occupation distribution; in particular, the occupation of central galaxies does not reach unity for the most massive haloes, and drops with increasing mass. The glam catalogues reproduce the abundance and clustering of the LRGs predicted by galform. We use the glam mocks to compute the covariance matrices for the two-point correlation function and power spectrum of the LRGs and their background dark matter density field, revealing important differences. We also make predictions for the linear-growth rate and the baryon acoustic oscillations distances at z = 0.6, 0.74, and 0.93. All ‘DESI-like’ LRG catalogues are made publicly available.

(117)Generalized BMS charge algebra
  • Miguel Campiglia,
  • Javier Peraza
Physical Review D (05/2020) doi:10.1103/PhysRevD.101.104039
abstract + abstract -

It has been argued that the symmetries of gravity at null infinity should include a Diff (S2) factor associated with diffeomorphisms on the celestial sphere. However, the standard phase space of gravity does not support the action of such transformations. Building on earlier work by Laddha and one of the authors, we present an extension of the phase space of gravity at null infinity on which Diff (S2) acts canonically. The Poisson brackets of supertranslation and Diff (S2) charges reproduce the generalized BMS algebra introduced in [Campiglia and Laddha Phys. Rev. D 90, 124028 (2014), 10.1103/PhysRevD.90.124028].

(116)Understanding the Fundamental Plane and the Tully Fisher Relation
  • Jeremy Mould
Frontiers in Astronomy and Space Sciences (05/2020) doi:10.3389/fspas.2020.00021
abstract + abstract -

The relation between early type galaxy size, surface brightness and velocity dispersion, ``the fundamental plane", has long been understood as resulting from equilibrium in their largely pressure supported stellar dynamics. The dissipation and feedback involved in reaching such an equilibrium through merger formation of these galaxies over cosmic time can be responsible for the orientation of the plane. We see a correlation between surface brightness enhancement and youth in the 6dF Galaxy Survey. Correlations of this `tilt' with stellar mass, age, concentration, shape and metallicity now point the direction for further work on the resolved kinematics and structure of these nearby galaxies and on their initial mass function and dark matter component. On the face of it, the Tully Fisher relation is a simpler one dimensional scaling relation. However, as late type galaxies have bulges as well as disks, and, as the surface density of disks is only standard for the more massive galaxies, additional parameters are involved.

(115)Testing the origin of the "f<SUB>1</SUB>(1420 ) " with the K ¯ p →Λ (Σ )K K ¯ π reaction
  • Wei-Hong Liang,
  • E. Oset
European Physical Journal C (05/2020) doi:10.1140/epjc/s10052-020-7966-y
abstract + abstract -

We study the K ¯ p →Y K K ¯ π reactions with K ¯ =K¯ 0,K- and Y =Σ0+,Λ , in the region of K K ¯ π invariant masses of 1200 -1550 MeV. The strong coupling of the f1(1285 ) resonance to KK ¯ makes the mechanism based on K exchange very efficient to produce this resonance observed in the K K ¯ π invariant mass distribution. In addition, in all these reactions one observes an associated peak at 1420 MeV which comes from the KK ¯ decay mode of the f1(1285 ) when the K is placed on shell at higher invariant masses. We call the attention to the possibility that the peaks observed in other reactions where the "f1(1420 ) " is observed have a similar origin.

(114)Cosmology dependence of galaxy cluster scaling relations
  • Priyanka Singh,
  • Alex Saro,
  • Matteo Costanzi,
  • Klaus Dolag
Monthly Notices of the Royal Astronomical Society (05/2020) doi:10.1093/mnras/staa1004
abstract + abstract -

The abundance of galaxy clusters as a function of mass and redshift is a well known powerful cosmological probe, which relies on underlying modelling assumptions on the mass-observable relations (MOR). Some of the MOR parameters can be constrained directly from multi-wavelength observations, as the normalization at some reference cosmology, the mass-slope, the redshift evolution, and the intrinsic scatter. However, the cosmology dependence of MORs cannot be tested with multi-wavelength observations alone. We use magneticum simulations to explore the cosmology dependence of galaxy cluster scaling relations. We run fifteen hydrodynamical cosmological simulations varying Ωm, Ωb, h0, and σ8 (around a reference cosmological model). The MORs considered are gas mass, baryonic mass, gas temperature, Y and velocity dispersion as a function of virial mass. We verify that the mass and redshift slopes and the intrinsic scatter of the MORs are nearly independent of cosmology with variations significantly smaller than current observational uncertainties. We show that the gas mass and baryonic mass sensitively depends only on the baryon fraction, velocity dispersion, and gas temperature on h0, and Y on both baryon fraction and h0. We investigate the cosmological implications of our MOR parametrization on a mock catalogue created for an idealized eROSITA-like experiment. We show that our parametrization introduces a strong degeneracy between the cosmological parameters and the normalization of the MOR. Finally, the parameter constraints derived at different overdensity (Δ500c), for X-ray bolometric gas luminosity, and for different subgrid physics prescriptions are shown in the appendix.

(113)Encounters of merger and accretion shocks in galaxy clusters and their effects on intracluster medium
  • Congyao Zhang,
  • Eugene Churazov,
  • Klaus Dolag,
  • William R. Forman,
  • Irina Zhuravleva
Monthly Notices of the Royal Astronomical Society (05/2020) doi:10.1093/mnras/staa1013
abstract + abstract -

Several types/classes of shocks naturally arise during formation and evolution of galaxy clusters. One such class is represented by accretion shocks, associated with deceleration of infalling baryons. Such shocks, characterized by a very high Mach number, are present even in 1D models of cluster evolution. Another class is composed of 'runaway merger shocks', which appear when a merger shock, driven by a sufficiently massive infalling subcluster, propagates away from the main-cluster centre. We argue that, when the merger shock overtakes the accretion shock, a new long-living shock is formed that propagates to large distances from the main cluster (well beyond its virial radius), affecting the cold gas around the cluster. We refer to these structures as Merger-accelerated Accretion shocks (MA-shocks) in this paper. We show examples of such MA-shocks in one-dimensioanal (1D) and three-dimensional (3D) simulations and discuss their characteristic properties. In particular, (1) MA-shocks shape the boundary separating the hot intracluster medium (ICM) from the unshocked gas, giving this boundary a 'flower-like' morphology. In 3D, MA-shocks occupy space between the dense accreting filaments. (2) Evolution of MA-shocks highly depends on the Mach number of the runaway merger shock and the mass accretion rate parameter of the cluster. (3) MA-shocks may lead to the misalignment of the ICM boundary and the splashback radius.

(112)Quark structure of the χ<SUB>c</SUB>(3 P ) and X(4274) resonances and their strong and radiative decays
  • J. Ferretti,
  • E. Santopinto,
  • M. Naeem Anwar,
  • Yu Lu
European Physical Journal C (05/2020) doi:10.1140/epjc/s10052-020-8032-5
abstract + abstract -

We calculate the masses of χc(3 P ) states with threshold corrections in a coupled-channel model. The model was recently applied to the description of the properties of χc(2 P ) and χb(3 P ) multiplets (Ferretti and Santopinto in Phys Lett B 789:550, 2019]. We also compute the open-charm strong decay widths of the χc(3 P ) states and their radiative transitions. According to our predictions, the χc(3 P ) states should be dominated by the charmonium core, but they may also show small meson-meson components. The X(4274) is interpreted as a c c ¯ χc 1(3 P ) state. More information on the other members of the χc(3 P ) multiplet, as well as a more rigorous analysis of the X(4274)'s decay modes, are needed to provide further indications on the quark structure of the previous resonance.

(111)Electric dipole moments in a leptoquark scenario for the B-physics anomalies
  • Wolfgang Altmannshofer,
  • Stefania Gori,
  • Hiren H. Patel,
  • Stefano Profumo,
  • Douglas Tuckler
Journal of High Energy Physics (05/2020) doi:10.1007/JHEP05(2020)069
abstract + abstract -

Vector leptoquarks can address the lepton flavor universality anomalies in decays associated with the b → cℓν and b → sℓℓ transitions, as observed in recent years. While not required to explain the anomalies, these leptoquarks generically yield new sources of CP violation. In this paper, we explore constraints and discovery potential for electric dipole moments (EDMs) in leptonic and hadronic systems. We provide the most generic expressions for dipole moments induced by vector leptoquarks at one loop. We find that O(1) CP-violating phases in tau and muon couplings can lead to corresponding EDMs within reach of next-generation EDM experiments, and that existing bounds on the electron EDM already put stringent constraints on CP-violating electron couplings.

(110)On the origin of magnetic driven winds and the structure of the galactic dynamo in isolated galaxies
  • Ulrich P. Steinwandel,
  • Klaus Dolag,
  • Harald Lesch,
  • Benjamin P. Moster,
  • Andreas Burkert
  • +1
Monthly Notices of the Royal Astronomical Society (05/2020) doi:10.1093/mnras/staa817
abstract + abstract -

We investigate the build-up of the galactic dynamo and subsequently the origin of a magnetic driven outflow. We use a set-up of an isolated disc galaxy with a realistic circum-galactic medium (CGM). We find good agreement of the galactic dynamo with theoretical and observational predictions from the radial and toroidal components of the magnetic field as function of radius and disc scale height. We find several field reversals indicating dipole structure at early times and quadrupole structure at late times. Together with the magnetic pitch angle and the dynamo control parameters Rα, Rω, and D, we present strong evidence for an α2-Ω dynamo. The formation of a bar in the centre leads to further amplification of the magnetic field via adiabatic compression which subsequently drives an outflow. Due to the Parker instability the magnetic field lines rise to the edge of the disc, break out, and expand freely in the CGM driven by the magnetic pressure. Finally, we investigate the correlation between magnetic field and star formation rate. Globally, we find that the magnetic field is increasing as function of the star formation rate surface density with a slope between 0.3 and 0.45 in good agreement with predictions from theory and observations. Locally, we find that the magnetic field can decrease while star formation increases. We find that this effect is correlated with the diffusion of magnetic field from the spiral arms to the interarm regions which we explicitly include by solving the induction equation and accounting for non-linear terms.

(109)The H I mass function of group galaxies in the ALFALFA survey
  • Michael G. Jones,
  • Kelley M. Hess,
  • Elizabeth A. K. Adams,
  • Lourdes Verdes-Montenegro
Monthly Notices of the Royal Astronomical Society (05/2020) doi:10.1093/mnras/staa810
abstract + abstract -

We estimate the H I mass function (HIMF) of galaxies in groups based on thousands of ALFALFA (Arecibo Legacy Fast ALFA survey) H I detections within the galaxy groups of four widely used SDSS (Sloan Digital Sky Survey) group catalogues. Although differences between the catalogues mean that there is no one definitive group galaxy HIMF, in general we find that the low-mass slope is flat, in agreement with studies based on small samples of individual groups, and that the 'knee' mass is slightly higher than that of the global HIMF of the full ALFALFA sample. We find that the observed fraction of ALFALFA galaxies in groups is approximately 22 per cent. These group galaxies were removed from the full ALFALFA source catalogue to calculate the field HIMF using the remaining galaxies. Comparison between the field and group HIMFs reveals that group galaxies make only a small contribution to the global HIMF as most ALFALFA galaxies are in the field, but beyond the HIMF 'knee' group galaxies dominate. Finally, we attempt to separate the group galaxy HIMF into bins of group halo mass, but find that too few low-mass galaxies are detected in the most massive groups to tightly constrain the slope, owing to the rarity of such groups in the nearby Universe where low-mass galaxies are detectable with existing H I surveys.

(108)Direct Measurement of the H I-halo Mass Relation through Stacking
  • Hong Guo,
  • Michael G. Jones,
  • Martha P. Haynes,
  • Jian Fu
The Astrophysical Journal (05/2020) doi:10.3847/1538-4357/ab886f
abstract + abstract -

We present accurate measurements of the total H I mass in dark matter halos of different masses at z ∼ 0, by stacking the H I spectra of entire groups from the Arecibo Fast Legacy ALFA Survey. The halos are selected from the optical galaxy group catalog constructed from the Sloan Digital Sky Survey DR7 Main Galaxy sample, with reliable measurements of halo mass and halo membership. We find that the H I-halo mass relation is not a simple monotonic function, as assumed in several theoretical models. In addition to the dependence of halo mass, the total H I gas mass shows a strong dependence on the halo richness, with larger H I masses in groups with more members at fixed halo masses. Moreover, halos with at least three member galaxies in the group catalog have a sharp decrease of the H I mass, potentially caused by the virial halo shock-heating and the active galactic nucleus (AGN) feedback. The dominant contribution of the H I gas comes from the central galaxies for halos of ${M}_{{\rm{h}}}\lt {10}^{12.5}{h}^{-1}{M}_{\odot }$ , while the satellite galaxies dominate over more massive halos. Our measurements are consistent with a three-phase formation scenario of the H I-rich galaxies. The smooth cold gas accretion is driving the H I mass growth in halos of ${M}_{{\rm{h}}}\lt {10}^{11.8}{h}^{-1}{M}_{\odot }$ , with late-forming halos having more H I accreted. The virial halo shock-heating and AGN feedback will take effect to reduce the H I supply in halos of ${10}^{11.8}{h}^{-1}{M}_{\odot }\lt {M}_{{\rm{h}}}\lt {10}^{13}{h}^{-1}{M}_{\odot }$ . The H I mass in halos more massive than ${10}^{13}{h}^{-1}{M}_{\odot }$ generally grows by mergers, with the dependence on halo richness becoming much weaker.

(107)The synthetic Emission Line COSMOS catalogue: Hα and [O II] galaxy luminosity functions and counts at 0.3 < z < 2.5
  • Shun Saito,
  • Sylvain de la Torre,
  • Olivier Ilbert,
  • Cédric Dubois,
  • Kiyoto Yabe
  • +1
MNRAS (05/2020) doi:10.1093/mnras/staa727
abstract + abstract -

Star-forming galaxies with strong nebular and collisional emission lines are privileged target galaxies in forthcoming cosmological large galaxy redshift surveys. We use the COSMOS2015 photometric catalogue to model galaxy spectral energy distributions and emission-line fluxes. We adopt an empirical but physically motivated model that uses information from the best-fitting spectral energy distribution of stellar continuum to each galaxy. The emission-line flux model is calibrated and validated against direct flux measurements in subsets of galaxies that have 3D-HST or zCOSMOS-Bright spectra. We take a particular care in modelling dust attenuation such that our model can explain both Hα and [O II] observed fluxes at different redshifts. We find that a simple solution to this is to introduce a redshift evolution in the dust attenuation fraction parameter, f = Estar(B - V)/Egas(B - V), as f(z) = 0.44 + 0.2z. From this catalogue, we derive the Hα and [O II] luminosity functions up to redshifts of about 2.5 after carefully accounting for emission line flux and redshift errors. This allows us to make predictions for Hα and [O II] galaxy number counts in next-generation cosmological redshift surveys. Our modelled emission lines and spectra in the COSMOS2015 catalogue shall be useful to study the target selection for planned next-generation galaxy redshift surveys and we make them publicly available as 'EL-COSMOS' on the ASPIC data base.

(106)Properties of gamma-ray decay lines in 3D core-collapse supernova models, with application to SN 1987A and Cas A
  • A. Jerkstrand,
  • A. Wongwathanarat,
  • H. -T. Janka,
  • M. Gabler,
  • D. Alp
  • +6
  • R. Diehl,
  • K. Maeda,
  • J. Larsson,
  • C. Fransson,
  • A. Menon,
  • A. Heger
  • (less)
Monthly Notices of the Royal Astronomical Society (05/2020) doi:10.1093/mnras/staa736
abstract + abstract -

Comparison of theoretical line profiles to observations provides important tests for supernova explosion models. We study the shapes of radioactive decay lines predicted by current 3D core-collapse explosion simulations, and compare these to observations of SN 1987A and Cas A. Both the widths and shifts of decay lines vary by several thousand kilometres per second depending on viewing angle. The line profiles can be complex with multiple peaks. By combining observational constraints from 56Co decay lines, 44Ti decay lines, and Fe IR lines, we delineate a picture of the morphology of the explosive burning ashes in SN 1987A. For MZAMS = 15-20 M progenitors exploding with ∼1.5 × 1051 erg, ejecta structures suitable to reproduce the observations involve a bulk asymmetry of the 56Ni of at least ∼400 km s-1 and a bulk velocity of at least 1500 km s-1. By adding constraints to reproduce the UVOIR bolometric light curve of SN 1987A up to 600 d, an ejecta mass around 14 M is favoured. We also investigate whether observed decay lines can constrain the neutron star (NS) kick velocity. The model grid provides a constraint VNS > Vredshift, and applying this to SN 1987A gives a NS kick of at least 500 km s-1. For Cas A, our single model provides a satisfactory fit to the NuSTAR observations and reinforces the result that current neutrino-driven core-collapse SN models achieve enough bulk asymmetry in the explosive burning material. Finally, we investigate the internal gamma-ray field and energy deposition, and compare the 3D models to 1D approximations.

(105)Asymmetric spatial distribution of subsolar metallicity stars in the Milky Way nuclear star cluster
  • A. Feldmeier-Krause,
  • W. Kerzendorf,
  • T. Do,
  • F. Nogueras-Lara,
  • N. Neumayer
  • +8
  • C. J. Walcher,
  • A. Seth,
  • R. Schödel,
  • P. T. de Zeeuw,
  • M. Hilker,
  • Nora Lützgendorf,
  • H. Kuntschner,
  • M. Kissler-Patig
  • (less)
abstract + abstract -

We present stellar metallicity measurements of more than 600 late-type stars in the central 10 pc of the Galactic centre. Together with our previously published KMOS data, this data set allows us to investigate, for the first time, spatial variations of the nuclear star cluster's metallicity distribution. Using the integral-field spectrograph KMOS (VLT) we observed almost half of the area enclosed by the nuclear star cluster's effective radius. We extract spectra at medium spectral resolution, and apply full spectral fitting utilising the PHOENIX library of synthetic stellar spectra. The stellar metallicities range from [M/H]=-1.25 dex to [M/H]> +0.3 dex, with most of the stars having super-solar metallicity. We are able to measure an anisotropy of the stellar metallicity distribution. In the Galactic North, the portion of sub-solar metallicity stars with [M/H]<0.0 dex is more than twice as high as in the Galactic South. One possible explanation for different fractions of sub-solar metallicity stars in different parts of the cluster is a recent merger event. We propose to test this hypothesis with high-resolution spectroscopy, and by combining the metallicity information with kinematic data.

(104)Black Hole Superradiant Instability from Ultralight Spin-2 Fields
  • Richard Brito,
  • Sara Grillo,
  • Paolo Pani
Physical Review Letters (05/2020) doi:10.1103/PhysRevLett.124.211101
abstract + abstract -

Ultralight bosonic fields are compelling dark-matter candidates and arise in a variety of beyond standard model scenarios. These fields can tap energy and angular momentum from spinning black holes through superradiant instabilities, during which a macroscopic bosonic condensate develops around the black hole. Striking features of this phenomenon include gaps in the spin-mass distribution of astrophysical black holes and a continuous gravitational-wave (GW) signal emitted by the condensate. So far these processes have been studied in great detail for scalar fields and, more recently, for vector fields. Here we take an important step forward in the black hole superradiance program by computing, analytically, the instability timescale, direct GW emission, and stochastic background, in the case of massive tensor (i.e., spin-2) fields. Our analysis is valid for any black hole spin and for small boson masses. The instability of massive spin-2 fields shares some properties with the scalar and vector cases, but its phenomenology is much richer, for example, there exist multiple modes with comparable instability timescales, and the dominant GW signal is hexadecapolar rather than quadrupolar. Electromagnetic and GW observations of spinning black holes in the mass range M ∈(1 ,1010) M can constrain the mass of a putative spin-2 field in the range 10-22≲mb c2/eV ≲10-10 . For 10-17≲mb c2/eV ≲10-15 , the space mission LISA could detect the continuous GW signal for sources at redshift z =20 , or even larger.

(103)ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT). I. CO, CS, CN, and H<SUB>2</SUB>CO around DG Tau B
  • A. Garufi,
  • L. Podio,
  • C. Codella,
  • K. Rygl,
  • F. Bacciotti
  • +5
  • S. Facchini,
  • D. Fedele,
  • A. Miotello,
  • R. Teague,
  • L. Testi
  • (less)
Astronomy and Astrophysics (04/2020) doi:10.1051/0004-6361/201937247
abstract + abstract -

The chemical composition of planets is determined by the distribution of the various molecular species in the protoplanetary disk at the time of their formation. To date, only a handful of disks have been imaged in multiple spectral lines with high spatial resolution. As part of a small campaign devoted to the chemical characterization of disk-outflow sources in Taurus, we report on new ALMA Band 6 (~1.3 mm) observations with ~0.15'' (20 au) resolution toward the embedded young star DG Tau B. Images of the continuum emission reveals a dust disk with rings and, putatively, a leading spiral arm. The disk, as well as the prominent outflow cavities, are detected in CO, H2CO, CS, and CN; instead, they remain undetected in SO2, HDO, and CH3OH. From the absorption of the back-side outflow, we inferred that the disk emission is optically thick in the inner 50 au. This morphology explains why no line emission is detected from this inner region and poses some limitations toward the calculation of the dust mass and the characterization of the inner gaseous disk. The H2CO and CS emission from the inner 200 au is mostly from the disk, and their morphology is very similar. The CN emission significantly differs from the other two molecules as it is observed only beyond 150 au. This ring-like morphology is consistent with previous observations and the predictions of thermochemical disk models. Finally, we constrained the disk-integrated column density of all molecules. In particular, we found that the CH3OH/H2CO ratio must be smaller than ~2, making the methanol non-detection still consistent with the only such ratio available from the literature (1.27 in TW Hya).

The reduced datacubes are only available at the CDS via anonymous ftp to ( or via

(102)The Optimal Strategy for ɛ <SUP>‧</SUP>/ɛ in the SM: 2019
  • Andrzej J. Buras
Journal of Physics Conference Series (04/2020) doi:10.1088/1742-6596/1526/1/012019
abstract + abstract -

Following the recent analysis done in collaboration with Jason Aebischer and Christoph Bobeth, I summarize the optimal, in our view, strategy for the present evaluation of the ratio ɛ /ɛ in the Standard Model. In particular, I emphasize the importance of the correct matching of the long-distance and short-distance contributions to ɛ /ɛ, which presently is only achieved by RBC-UKQCD lattice QCD collaboration and by the analytical Dual QCD approach. An important role play also the isospin-breaking and QED effects, which presently are best known from chiral perturbation theory, albeit still with a significant error. Finally, it is essential to include NNLO QCD corrections in order to reduce unphysical renormalization scheme and scale dependences present at the NLO level. Here µ c in m cc ) in the case of QCD penguin contributions and µ t in m tt ) in the case of electroweak penguin contributions play the most important roles. Presently the error on ɛ /ɛ is dominated by the uncertainties in the QCDP parameter B_6(1/2) and the isospin-breaking parameter \hat Ω {{eff}}. We present a table illustrating this.

(101)Kinematics of simulated galaxies II: Probing the stellar kinematics of galaxies out to large radii
  • Felix Schulze,
  • Rhea-Silvia Remus,
  • Klaus Dolag,
  • Sabine Bellstedt,
  • Andreas Burkert
  • +1
Monthly Notices of the Royal Astronomical Society (04/2020) doi:10.1093/mnras/staa511
abstract + abstract -

We investigate the stellar kinematics of a sample of galaxies extracted from the hydrodynamic cosmological Magneticum Pathfinder simulations out to five half-mass radii. We construct differential radial stellar spin profiles quantified by the observationally widely used λ and the closely related (V/σ) parameters. We find three characteristic profile shapes: profiles exhibiting a (I) peak within 2.5 half-mass radii and a subsequent decrease; (II) continuous increase that plateaus at larger radii typically with a high amplitude; (III) completely flat behaviour typically with low amplitude, in agreement with observations. This shows that the kinematic state of the stellar component can vary significantly with radius, suggesting a distinct interplay between in-situ star formation and ex-situ accretion of stars. Following the evolution of our sample through time, we provide evidence that the accretion history of galaxies with decreasing profiles is dominated by the anisotropic accretion of low-mass satellites that get disrupted beyond ∼2.0 half-mass radii, building up a stellar halo with non-ordered motion while maintaining the central rotation already present at z = 2. In fact, at z = 2 decreasing profiles are the predominant profile class. Hence, we can predict a distinct formation pathway for galaxies with a decreasing profile and show that the centre resembles an old embedded disc. Furthermore, we show that the radius of the kinematic transition provides a good estimation for the transition radius from in-situ stars in the centre to accreted stars in the halo.

(100)Thermal Relic Targets with Exponentially Small Couplings
  • Raffaele Tito D'Agnolo,
  • Duccio Pappadopulo,
  • Joshua T. Ruderman,
  • Po-Jen Wang
Physical Review Letters (04/2020) doi:10.1103/PhysRevLett.124.151801
abstract + abstract -

If dark matter was produced in the early Universe by the decoupling of its annihilations into known particles, there is a sharp experimental target for the size of its coupling. We show that if dark matter was produced by inelastic scattering against a lighter particle from the thermal bath, then its coupling can be exponentially smaller than the coupling required for its production from annihilations. As an application, we demonstrate that dark matter produced by inelastic scattering against electrons provides new thermal relic targets for direct detection and fixed target experiments.

(99)Linear point and sound horizon as purely geometric standard rulers
  • Márcio O'Dwyer,
  • Stefano Anselmi,
  • Glenn D. Starkman,
  • Pier-Stefano Corasaniti,
  • Ravi K. Sheth
  • +1
Physical Review D (04/2020) doi:10.1103/PhysRevD.101.083517
abstract + abstract -

The baryon acoustic oscillations feature (BAO) imprinted in the clustering correlation function is known to furnish us cosmic distance determinations that are independent of the cosmological-background model and the primordial perturbation parameters. These measurements can be accomplished rigorously by means of the purely geometric BAO methods. To date two different purely geometric BAO approaches have been proposed. The first exploits the linear-point standard ruler. The second, called correlation-function model-fitting, exploits the sound-horizon standard ruler. A key difference between them is that, when estimated from clustering data, the linear point makes use of a cosmological-model-independent procedure to extract the ratio of the ruler to the cosmic distance, while the correlation-function model-fitting relies on a phenomenological cosmological model for the correlation function. Nevertheless the two rulers need to be precisely defined independently of any specific observable (e.g., the BAO). We define the linear point and sound horizon and we fully characterize and compare the two rulers' cosmological-parameter dependence. We find that they are both geometrical (i.e., independent of the primordial cosmological parameters) within the required accuracy, and that they have the same parameter dependence for a wide range of parameter values. We estimate the rulers' best-fit values and errors, given the cosmological constraints obtained by the Planck Satellite team from their measurements of the cosmic microwave background temperature and polarization anisotropies. We do this for three different cosmological models encompassed by the purely geometric BAO methods. In each case we find that the relative errors of the two rulers coincide and they are insensitive to the assumed cosmological model. Interestingly both the linear point and the sound horizon shift by 0.5 σ when we do not fix the spatial geometry to be flat in Λ CDM . This points toward a sensitivity of the rulers to different cosmological models when they are estimated from the cosmic microwave background.

(98)J /ψ p scattering length from GlueX threshold measurements
  • Igor I. Strakovsky,
  • Denis Epifanov,
  • Lubomir Pentchev
Physical Review C (04/2020) doi:10.1103/PhysRevC.101.042201
abstract + abstract -

The quality of the recent GlueX J /ψ photoproduction data from Hall D at Jefferson Laboratory and the proximity of the data to the energy threshold, gives access to a variety of interesting physics aspects. As an example, an estimation of the J /ψ -nucleon scattering length αJ /ψ p is provided within the vector meson dominance model. It results in | αJ /ψ p|=(3.08 ±0.55 (stat . ) ±0.42 (syst . ) ) mfm which is much smaller than a typical size of a hadron.

(97)Gravitational Wave from Axion-SU(2) Gauge Fields: Effective Field Theory for Kinetically Driven Inflation
  • Yuki Watanabe,
  • Eiichiro Komatsu
arXiv e-prints (04/2020) e-Print:2004.04350
abstract + abstract -

Building on Weinberg's approach to effective field theory for inflation, we construct an effective Lagrangian for a pseudo scalar (axion) inflaton field with shift symmetry. In this Lagrangian we allow the axion field to couple to non-Abelian gauge fields via a Chern-Simons term. We then analyze a class of inflation models driven by kinetic terms. We find that the observational constraints on the amplitudes of curvature perturbations and non-Gaussianity yield a lower bound for the tensor-to-scalar ratio of $r\gtrsim 5\times 10^{-3}$ from the vacuum fluctuation. The sourced gravitational wave from SU(2) gauge fields further increases the tensor-to-scalar ratio and makes the total gravitational wave partially chiral and non-Gaussian, which can be probed by polarization of the cosmic microwave background and direct detection experiments. We discuss constraints on parameter space due to backreaction of spin-2 particles produced by the gauge field.

(96)Small-scale Structure Traced by Neutral Hydrogen Absorption in the Direction of Multiple-component Radio Continuum Sources
  • Daniel R. Rybarczyk,
  • Snezana Stanimirović,
  • Ellen G. Zweibel,
  • Claire E. Murray,
  • John M. Dickey
  • +2
The Astrophysical Journal (04/2020) doi:10.3847/1538-4357/ab83f7
abstract + abstract -

We have studied the small-scale distribution of atomic hydrogen (H I) using 21 cm absorption spectra against multiple-component background radio continuum sources from the 21-SPONGE survey and the Millennium Arecibo Absorption-Line Survey. We have found >5σ optical depth variations at a level of ∼0.03-0.5 between 13 out of 14 adjacent sightlines separated by a few arcseconds to a few arcminutes, suggesting the presence of neutral structures on spatial scales from a few to thousands of au (which we refer to as tiny-scale atomic structure, TSAS). The optical depth variations are strongest in directions where the H I column density and the fraction of H I in the cold neutral medium (CNM) are highest, which tend to be at low Galactic latitudes. By measuring changes in the properties of Gaussian components fitted to the absorption spectra, we find that changes in both the peak optical depth and the linewidth of TSAS absorption features contribute to the observed optical depth variations, while changes in the central velocity do not appear to strongly impact the observed variations. Both thermal and turbulent motions contribute appreciably to the linewidths, but the turbulence does not appear strong enough to confine overpressured TSAS. In a majority of cases, the TSAS column densities are sufficiently high that these structures can radiatively cool fast enough to maintain thermal equilibrium with their surroundings, even if they are overpressured. We also find that a majority of TSAS is associated with the CNM. For TSAS in the direction of the Taurus molecular cloud and the local Leo cold cloud, we estimate densities over an order of magnitude higher than typical CNM densities.

(95)UV sensitivity of the axion mass from instantons in partially broken gauge groups
  • Csaba Csáki,
  • Maximilian Ruhdorfer,
  • Yuri Shirman
Journal of High Energy Physics (04/2020) doi:10.1007/JHEP04(2020)031
abstract + abstract -

We examine the contribution of small instantons to the axion mass in various UV completions of QCD. We show that the reason behind the potential dominance of such contributions is the non-trivial embedding of QCD into the UV theory. The effects from instantons in the partially broken gauge group appear as "fractional instanton" corrections in the effective theory. These will exhibit unusual dependences on the various scales in the problem whenever the index of embedding is non-trivial. We present a full one-instanton calculation of the axion mass in the simplest product group models, carefully keeping track of numerical prefactors. Rather than using a 't Hooft operator approximation we directly evaluate the contributions to the vacuum bubble, automatically capturing the effects of closing up external fermion lines with Higgs loops. This approach is manifestly finite and removes the uncertainty associated with introducing a cutoff scale for the Higgs loops. We verify that the small instantons may dominate over the QCD contribution for very high breaking scales and at least three group factors.

(94)Polarized Initial States of Primordial Gravitational Waves
  • Sugumi Kanno,
  • Jiro Soda
Symmetry (04/2020) doi:10.3390/sym12040672
abstract + abstract -

Polarizations of primordial gravitational waves can be relevant when considering inflationary universe in modified gravity or when matter fields survive during inflation. Such polarizations have been discussed in the Bunch-Davies vacuum. Instead of taking into account dynamical generation of polarizations of gravitational waves, in this paper, we consider polarized initial states constructed from $SU(2)$ coherent states. We then evaluate the power spectrums of the primordial gravitational waves in the states.

(93)Clustering of B ¯→D<SUP>(∗)</SUP>τ<SUP>-</SUP>ν<SUB>¯τ</SUB> kinematic distributions with ClusterKinG
  • Jason Aebischer,
  • Thomas Kuhr,
  • Kilian Lieret
Journal of High Energy Physics (04/2020) doi:10.1007/JHEP04(2020)007
abstract + abstract -

New Physics can manifest itself in kinematic distributions of particle decays. The parameter space defining the shape of such distributions can be large which is chalenging for both theoretical and experimental studies. Using clustering algorithms, the parameter space can however be dissected into subsets (clusters) which correspond to similar kinematic distributions. Clusters can then be represented by benchmark points, which allow for less involved studies and a concise presentation of the results. We demonstrate this concept using the Python package ClusterKinG, an easy to use framework for the clustering of distributions that particularly aims to make these techniques more accessible in a High Energy Physics context. As an example we consider B ¯→D(∗)τ-ν¯τ distributions and discuss various clustering methods and possible implications for future experimental analyses.

(92)The Schrödinger-Poisson method for Large-Scale Structure
  • Mathias Garny,
  • Thomas Konstandin,
  • Henrique Rubira
abstract + abstract -

We study the Schrödinger-Poisson (SP) method in the context of cosmological large-scale structure formation in an expanding background. In the limit ℏ→0, the SP technique can be viewed as an effective method to sample the phase space distribution of cold dark matter that remains valid on non-linear scales. We present results for the 2D and 3D matter correlation function and power spectrum at length scales corresponding to the baryon acoustic oscillation (BAO) peak. We discuss systematic effects of the SP method applied to cold dark matter and explore how they depend on the simulation parameters. In particular, we identify a combination of simulation parameters that controls the scale-independent loss of power observed at low redshifts, and discuss the scale relevant to this effect.

(91)Planet-induced Vortices with Dust Coagulation in Protoplanetary Disks
  • Ya-Ping Li,
  • Hui Li,
  • Shengtai Li,
  • Tilman Birnstiel,
  • Joanna Drążkowska
  • +1
The Astrophysical Journal (04/2020) doi:10.3847/2041-8213/ab7fb2
abstract + abstract -

In this work, we study how the dust coagulation/fragmentation will influence the evolution and observational appearances of vortices induced by a massive planet embedded in a low-viscosity disk by performing global 2D high-resolution hydrodynamical simulations. Within the vortex, due to its higher gas surface density and steeper pressure gradients, dust coagulation, fragmentation, and drift (to the vortex center) are all quite efficient, producing dust particles ranging from 1 μm to ∼1.0 cm, as well as an overall high dust-to-gas ratio (above unity). In addition, the dust size distribution is quite nonuniform inside the vortex, with the mass-weighted average dust size at the vortex center (∼4.0 mm) being a factor of ∼10 larger than other vortex regions. Both large (∼millimeter) and small (tens of microns) particles contribute strongly to affect the gas motion within the vortex. As such, we find that the inclusion of dust coagulation has a significant impact on the vortex lifetime and the typical vortex lifetime is about 1000 orbits. After the initial gaseous vortex is destroyed, the dust spreads into a ring with a few remaining smaller gaseous vortices with a high dust concentration and a large maximum size (∼millimeter). At late time, the synthetic dust continuum images for the coagulation case show as a ring inlaid with several hot spots at the 1.33 mm band, while only distinct hot spots remain at 7.0 mm.

(90)Heavy-Quark Expansion for B¯s→D(∗)s Form Factors and Unitarity Bounds beyond the SU(3)F Limit
  • Marzia Bordone,
  • Nico Gubernari,
  • Martin Jung,
  • Danny van Dyk
The European Physical Journal C (04/2020) e-Print:1912.09335 doi:10.1140/epjc/s10052-020-7850-9
abstract + abstract -

We carry out a comprehensive analysis of the full set of B¯q→D(∗)q form factors for spectator quarks q=u,d,s within the framework of the Heavy-Quark Expansion (HQE) to order O(αs,1/mb,1/m2c). In addition to the available lattice QCD calculations we make use of two new sets of theoretical constraints: we produce for the first time numerical predictions for the full set of B¯s→D(∗)s form factors using Light-Cone Sum Rules with Bs-meson distribution amplitudes. Furthermore, we reassess the QCD three-point sum rule results for the Isgur-Wise functions entering all our form factors for both q=u,d and q=s spectator quarks. These additional constraints allow us to go beyond the commonly used assumption of SU(3)F symmetry for the B¯s→D(∗)s form factors, especially in the unitarity constraints which we impose throughout our analysis. We find the coefficients of the IW functions emerging at O(1/m2c) to be consistent with the naive O(1) expectation, indicating a good convergence of the HQE. While we do not find significant SU(3) breaking, the explicit treatment of q=s as compared to a simple symmetry assumption renders the unitarity constraints more effective. We find that the (pseudo)scalar bounds are saturated to a large degree, which affects our theory predictions. We analyze the phenomenological consequences of our improved form factors by extracting |Vcb| from B¯→D(∗)ℓν decays and producing theoretical predictions for the lepton-flavour universality ratios R(D), R(D∗), R(Ds) and R(D∗s), as well as the τ- and D∗q polarization fractions for the B¯q→D(∗)qτν modes.

(89)Questioning the spatial origin of complex organic molecules in young protostars with the CALYPSO survey
  • A. Belloche,
  • A. J. Maury,
  • S. Maret,
  • S. Anderl,
  • A. Bacmann
  • +10
  • Ph. André,
  • S. Bontemps,
  • S. Cabrit,
  • C. Codella,
  • M. Gaudel,
  • F. Gueth,
  • C. Lefèvre,
  • B. Lefloch,
  • L. Podio,
  • L. Testi
  • (less)
Astronomy and Astrophysics (03/2020) doi:10.1051/0004-6361/201937352
abstract + abstract -

Context. Complex organic molecules (COMs) have been detected in a few Class 0 protostars but their origin is not well understood. While the usual picture of a hot corino explains their presence as resulting from the heating of the inner envelope by the nascent protostar, shocks in the outflow, disk wind, the presence of a flared disk, or the interaction region between envelope and disk at the centrifugal barrier have also been claimed to enhance the abundance of COMs.
Aims: Going beyond studies of individual objects, we want to investigate the origin of COMs in young protostars on a statistical basis.
Methods: We use the CALYPSO survey performed with the Plateau de Bure Interferometer of the Institut de Radioastronomie Millimétrique to search for COMs at high angular resolution in a sample of 26 solar-type protostars, including 22 Class 0 and four Class I objects. We derive the column densities of the detected molecules under the local thermodynamic equilibrium approximation and search for correlations between their abundances and with various source properties.
Results: Methanol is detected in 12 sources and tentatively in one source, which represents half of the sample. Eight sources (30%) have detections of at least three COMs. We find a strong chemical differentiation in multiple systems with five systems having one component with at least three COMs detected but the other component devoid of COM emission. All sources with a luminosity higher than 4 L have at least one detected COM whereas no COM emission is detected in sources with internal luminosity lower than 2 L, likely because of a lack of sensitivity. Internal luminosity is found to be the source parameter impacting the COM chemical composition of the sources the most, while there is no obvious correlation between the detection of COM emission and that of a disk-like structure. A canonical hot-corino origin may explain the COM emission in four sources, an accretion-shock origin in two or possibly three sources, and an outflow origin in three sources. The CALYPSO sources with COM detections can be classified into three groups on the basis of the abundances of oxygen-bearing molecules, cyanides, and CHO-bearing molecules. These chemical groups correlate neither with the COM origin scenarios, nor with the evolutionary status of the sources if we take the ratio of envelope mass to internal luminosity as an evolutionary tracer. We find strong correlations between molecules that are a priori not related chemically (for instance methanol and methyl cyanide), implying that the existence of a correlation does not imply a chemical link.
Conclusions: The CALYPSO survey has revealed a chemical differentiation in multiple systems that is markedly different from the case of the prototypical binary IRAS 16293-2422. This raises the question of whether all low-mass protostars go through a phase showing COM emission. A larger sample of young protostars and a more accurate determination of their internal luminosity will be necessary to make further progress. Searching for correlations between the COM emission and the jet/outflow properties of the sources may also be promising.

Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).

The CALYPSO calibrated visibility tables and maps are publicly available at

(88)Detectability of embedded protoplanets from hydrodynamical simulations
  • E. Sanchis,
  • G. Picogna,
  • B. Ercolano,
  • L. Testi,
  • G. Rosotti
Monthly Notices of the Royal Astronomical Society (03/2020) doi:10.1093/mnras/staa074
abstract + abstract -

We predict magnitudes for young planets embedded in transition discs, still affected by extinction due to material in the disc. We focus on Jupiter-sized planets at a late stage of their formation, when the planet has carved a deep gap in the gas and dust distributions and the disc starts to being transparent to the planet flux in the infrared (IR). Column densities are estimated by means of three-dimensional hydrodynamical models, performed for several planet masses. Expected magnitudes are obtained by using typical extinction properties of the disc material and evolutionary models of giant planets. For the simulated cases located at 5.2 au in a disc with a local unperturbed surface density of 127 g cm^{-2}, a 1MJ planet is highly extinct in the J, H, and Kbands, with predicted absolute magnitudes ≥ 50 mag. In the L and Mbands, extinction decreases, with planet magnitudes between 25 and 35 mag. In the Nband, due to the silicate feature on the dust opacities, the expected magnitude increases to ∼40 mag. For a 2MJ planet, the magnitudes in the J, H, and Kbands are above 22 mag, while for the L, M, and Nbands, the planet magnitudes are between 15 and 20 mag. For the 5MJ planet, extinction does not play a role in any IR band, due to its ability to open deep gaps. Contrast curves are derived for the transition discs in CQ Tau, PDS 70, HL Tau, TW Hya, and HD 163296. Planet mass upper limits are estimated for the known gaps in the last two systems.

(87)MSTAR - a fast parallelized algorithmically regularized integrator with minimum spanning tree coordinates
  • Antti Rantala,
  • Pauli Pihajoki,
  • Matias Mannerkoski,
  • Peter H. Johansson,
  • Thorsten Naab
Monthly Notices of the Royal Astronomical Society (03/2020) doi:10.1093/mnras/staa084
abstract + abstract -

We present the novel algorithmically regularized integration method MSTAR for high-accuracy (|ΔE/E| ≳ 10-14) integrations of N-body systems using minimum spanning tree coordinates. The twofold parallelization of the O(N_part^2) force loops and the substep divisions of the extrapolation method allow for a parallel scaling up to NCPU = 0.2 × Npart. The efficient parallel scaling of MSTAR makes the accurate integration of much larger particle numbers possible compared to the traditional algorithmic regularization chain (AR-CHAIN) methods, e.g. Npart = 5000 particles on 400 CPUs for 1 Gyr in a few weeks of wall-clock time. We present applications of MSTAR on few particle systems, studying the Kozai mechanism and N-body systems like star clusters with up to Npart = 104 particles. Combined with a tree or fast multipole-based integrator, the high performance of MSTAR removes a major computational bottleneck in simulations with regularized subsystems. It will enable the next-generation galactic-scale simulations with up to 109 stellar particles (e.g. m_\star = 100 M_⊙ for an M_\star = 10^{11} M_⊙ galaxy), including accurate collisional dynamics in the vicinity of nuclear supermassive black holes.

(86)Exploring the diversity of Type 1 active galactic nuclei identified in SDSS-IV/SPIDERS
  • Julien Wolf,
  • Mara Salvato,
  • Damien Coffey,
  • Andrea Merloni,
  • Johannes Buchner
  • +6
  • Riccardo Arcodia,
  • Dalya Baron,
  • Francisco J. Carrera,
  • Johan Comparat,
  • Donald P. Schneider,
  • Kirpal Nandra
  • (less)
Monthly Notices of the Royal Astronomical Society (03/2020) doi:10.1093/mnras/staa018
abstract + abstract -

We present a statistical analysis of the optical properties of an X-ray-selected Type 1 active galactic nucleus (AGN) sample, using high signal-to-noise ratio (S/N>20) spectra of the counterparts of the ROSAT/2RXS sources in the footprint of the SDSS-IV/SPIDERS (Spectroscopic IDentification of eROSITA Sources) programme. The final sample contains 2100 sources. It significantly extends the redshift and luminosity ranges (z ∼ 0.01-0.80 and L_{0.1-2.4 keV} ∼ 2.0 × 10^{41}-1.0 × 10^{46} erg s^{-1}) used so far in this kind of analysis. By means of a principal component analysis, we derive eigenvector (EV) 1 and 2 in an eleven-dimensional optical and X-ray parameter space, which are consistent with previous results. The validity of the correlations of the Eddington ratio L/LEdd with EV1 and the black hole mass with EV2 is strongly confirmed. These results imply that L/LEdd and black hole mass are related to the diversity of the optical properties of Type 1 AGNs. Investigating the relation of the width and asymmetry of H β and the relative strength of the iron emission r_{Fe II}, we show that our analysis supports the presence of a distinct kinematic region: the very broad line region. Furthermore, comparing sources with a red-asymmetric broad H β emission line to sources for which it is blue asymmetric, we find an intriguing difference in the correlation of the Fe II and the continuum emission strengths. We show that this contrasting behaviour is consistent with a flattened, stratified model of the broad-line region, in which the Fe II-emitting region is shielded from the central source.

(85)Three-dimensional simulations of clump formation in stellar wind collisions
  • D. Calderón,
  • J. Cuadra,
  • M. Schartmann,
  • A. Burkert,
  • J. Prieto
  • +1
Monthly Notices of the Royal Astronomical Society (03/2020) doi:10.1093/mnras/staa090
abstract + abstract -

The inner parsec of our Galaxy contains tens of Wolf-Rayet stars whose powerful outflows are constantly interacting while filling the region with hot, diffuse plasma. Theoretical models have shown that, in some cases, the collision of stellar winds can generate cold, dense material in the form of clumps. However, their formation process and properties are not well understood yet. In this work, we present, for the first time, a statistical study of the clump formation process in unstable wind collisions. We study systems with dense outflows (∼ 10^{-5} M_{⊙ } yr^{-1}), wind speeds of 500-1500 km s^{-1}, and stellar separations of ∼20-200 au. We develop three-dimensional high-resolution hydrodynamical simulations of stellar wind collisions with the adaptive-mesh refinement grid-based code RAMSES. We aim at characterizing the initial properties of clumps that form through hydrodynamic instabilities, mostly via the non-linear thin-shell instability (NTSI). Our results confirm that more massive clumps are formed in systems whose winds are close to the transition between the radiative and adiabatic regimes. Increasing either the wind speed or the degree of asymmetry increases the dispersion of the clump mass and ejection speed distributions. Nevertheless, the most massive clumps are very light (∼10-3-10^{-2} M_{\oplus }), about three orders of magnitude less massive than theoretical upper limits. Applying these results to the Galactic Centre, we find that clumps formed through the NTSI should not be heavy enough either to affect the thermodynamic state of the region or to survive for long enough to fall on to the central supermassive black hole.

(84)Fast neutrino flavor instability in the neutron-star convection layer of three-dimensional supernova models
  • Robert Glas,
  • H. -Thomas Janka,
  • Francesco Capozzi,
  • Manibrata Sen,
  • Basudeb Dasgupta
  • +2
  • Alessandro Mirizzi,
  • Günter Sigl
  • (less)
Physical Review D (03/2020) doi:10.1103/PhysRevD.101.063001
abstract + abstract -

It has been speculated for a long time that neutrinos from a supernova (SN) may undergo fast flavor conversions near the collapsed stellar core. We perform a detailed study of this intriguing possibility, for the first time analyzing two time-dependent state-of-the-art three-dimensional (3D) SN models of 9 M and 20 M from recent papers of Glas et al. Both models were computed with multidimensional three-flavor neutrino transport based on a two-moment solver, and both exhibit the presence of the so-called lepton-number emission self-sustained asymmetry (LESA). The transport solution does not provide the angular distributions of the flavor-dependent neutrino fluxes, which are crucial to track the fast flavor instability. To overcome this limitation, we use a recently proposed approach based on the angular moments of the energy-integrated electron lepton-number distribution up to second order, i.e., angle-energy integrals of the difference between νe and ν¯e phase-space distributions multiplied by corresponding powers of the unit vector of the neutrino velocity. With this method we find the possibility of fast neutrino flavor instability at radii smaller than ∼20 km , which is well interior to the neutrinosphere where neutrinos are still in the diffusive and near-equilibrium regime. Our results confirm recent observations in a two-dimensional (2D) (axisymmetric) SN model and in 2D and 3D models with a fixed matter background, which were computed with Boltzmann neutrino transport. However, the flavor unstable locations are not isolated points as discussed previously, but thin skins surrounding volumes where ν¯e are more abundant than νe. These volumes grow with time and appear first in the convective layer of the proto-neutron star (PNS), where a decreasing electron fraction and high temperatures favor the occurrence of regions with negative neutrino chemical potential. Since the electron fraction remains higher in the LESA dipole direction, where convective lepton-number transport out from the nonconvective PNS core slows down the deleptonization, flavor unstable conditions become more widespread in the opposite hemisphere. This interesting phenomenon deserves further investigation, since its impact on SN modeling and possible consequences for SN dynamics and neutrino observations are presently unclear.

(83)The Mira-Titan Universe. III. Emulation of the Halo Mass Function
  • Sebastian Bocquet,
  • Katrin Heitmann,
  • Salman Habib,
  • Earl Lawrence,
  • Thomas Uram
  • +3
  • Nicholas Frontiere,
  • Adrian Pope,
  • Hal Finkel
  • (less)
abstract + abstract -

We construct an emulator for the halo mass function over group and cluster mass scales for a range of cosmologies, including the effects of dynamical dark energy and massive neutrinos. The emulator is based on the recently completed Mira-Titan Universe suite of cosmological N-body simulations. The main set of simulations spans 111 cosmological models with 2.1 Gpc boxes. We extract halo catalogs in the redshift range z = [0.0, 2.0] and for masses . The emulator covers an eight-dimensional hypercube spanned by {, , , σ 8, h, n s , w 0, w a }; spatial flatness is assumed. We obtain smooth halo mass functions by fitting piecewise second-order polynomials to the halo catalogs and employ Gaussian process regression to construct the emulator while keeping track of the statistical noise in the input halo catalogs and uncertainties in the regression process. For redshifts z ≲ 1, the typical emulator precision is better than 2% for and <10% for . For comparison, fitting functions using the traditional universal form for the halo mass function can be biased at up to 30% at for z = 0. Our emulator is publicly available at

(82)Physical parameter space of bimetric theory and SN1a constraints
  • Marvin Lüben,
  • Angnis Schmidt-May,
  • Jochen Weller
abstract + abstract -

Bimetric theory describes a massless and a massive spin-2 field with fully non-linear (self-)interactions. It has a rich phenomenology and has been successfully tested with several data sets. However, the observational constraints have not been combined in a consistent framework, yet. We propose a parametrization of bimetric solutions in terms of the effective cosmological constant Λ and the mass mFP of the spin-2 field as well as its coupling strength to ordinary matter &baralpha;. This simplifies choosing priors in statistical analysis and allows to directly constrain these parameters with observational data not only from local systems but also from cosmology. By identifying the physical vacuum of bimetric theory these parameters are uniquely determined. We work out the new parametrization for various submodels and present the implied consistency constraints on the physical parameter space. As an application we derive observational constraints from SN1a on the physical parameters. We find that a large portion of the physical parameter space is in perfect agreement with current supernova data including self-accelerating models with a heavy spin-2 field.

(81)Type Ic supernova of a 22 M<SUB>⊙</SUB> progenitor
  • Jacob Teffs,
  • Thomas Ertl,
  • Paolo Mazzali,
  • Stephan Hachinger,
  • Thomas Janka
Monthly Notices of the Royal Astronomical Society (03/2020) doi:10.1093/mnras/staa123
abstract + abstract -

Type Ic supernovae (SNe Ic) are a sub-class of core-collapse SNe that exhibit no helium or hydrogen lines in their spectra. Their progenitors are thought to be bare carbon-oxygen cores formed during the evolution of massive stars that are stripped of their hydrogen and helium envelopes sometime before collapse. SNe Ic present a range of luminosities and spectral properties, from luminous GRB-SNe with broad-lined spectra to less luminous events with narrow-line spectra. Modelling SNe Ic reveals a wide range of both kinetic energies, ejecta masses, and 56Ni masses. To explore this diversity and how it comes about, light curves and spectra are computed from the ejecta following the explosion of an initially 22 M progenitor that was artificially stripped of its hydrogen and helium shells, producing a bare CO core of ∼5 M, resulting in an ejected mass of ∼4 M, which is an average value for SNe Ic. Four different explosion energies are used that cover a range of observed SNe. Finally, 56Ni and other elements are artificially mixed in the ejecta using two approximations to determine how element distribution affects light curves and spectra. The combination of different explosion energy and degree of mixing produces spectra that roughly replicate the distribution of near-peak spectroscopic features of SNe Ic. High explosion energies combined with extensive mixing can produce red, broad-lined spectra, while minimal mixing and a lower explosion energy produce bluer, narrow-lined spectra.

(80)Probing multicomponent FIMP scenarios with gamma-ray telescopes
  • Johannes Herms,
  • Alejandro Ibarra
Journal of Cosmology and Astroparticle Physics (03/2020) doi:10.1088/1475-7516/2020/03/026
abstract + abstract -

We consider a scenario where the dark sector includes two Feebly Interacting Massive Particles (FIMPs), with couplings to the Standard Model particles that allow their production in the Early Universe via thermal freeze-in. These couplings generically lead to the decay of the heavier dark matter component into the lighter, possibly leading to observable signals of the otherwise elusive FIMPs. Concretely, we argue that the loop induced decay ψ2→ψ1γ for fermionic FIMPs, or phi2→phi1γγ for scalar FIMPs, could have detectable rates for model parameters compatible with the observed dark matter abundance.

(79)CO2 reduction driven by a pH gradient
  • Reuben Hudson,
  • Ruvan de Graaf,
  • Mari Strandoo Rodin,
  • Aya Ohno,
  • Nick Lane
  • +6
  • Shawn E. McGlynn,
  • Yoichi M. A. Yamada,
  • Ryuhei Nakamura,
  • Laura M. Barge,
  • Dieter Braun,
  • and Victor Sojo
  • (less)
abstract + abstract -

All life on Earth is built of organic molecules, so the primordial sources of reduced carbon remain a major open question in studies of the origin of life. A variant of the alkaline-hydrothermal-vent theory for life’s emergence suggests that organics could have been produced by the reduction of CO2 via H2 oxidation, facilitated by geologically sustained pH gradients. The process would be an abiotic analog—and proposed evolutionary predecessor—of the Wood–Ljungdahl acetyl-CoA pathway of modern archaea and bacteria. The first energetic bottleneck of the pathway involves the endergonic reduction of CO2 with H2 to formate (HCOO–), which has proven elusive in mild abiotic settings. Here we show the reduction of CO2 with H2 at room temperature under moderate pressures (1.5 bar), driven by microfluidic pH gradients across inorganic Fe(Ni)S precipitates. Isotopic labeling with 13C confirmed formate production. Separately, deuterium (2H) labeling indicated that electron transfer to CO2 does not occur via direct hydrogenation with H2 but instead, freshly deposited Fe(Ni)S precipitates appear to facilitate electron transfer in an electrochemical-cell mechanism with two distinct half-reactions. Decreasing the pH gradient significantly, removing H2, or eliminating the precipitate yielded no detectable product. Our work demonstrates the feasibility of spatially separated yet electrically coupled geochemical reactions as drivers of otherwise endergonic processes. Beyond corroborating the ability of early-Earth alkaline hydrothermal systems to couple carbon reduction to hydrogen oxidation through biologically relevant mechanisms, these results may also be of significance for industrial and environmental applications, where other redox reactions could be facilitated using similarly mild approaches.

(78)Gas accretion damped by dust back-reaction at the snow line
  • Matías Gárate,
  • Til Birnstiel,
  • Joanna Drążkowska,
  • Sebastian Markus Stammler
Astronomy and Astrophysics (03/2020) doi:10.1051/0004-6361/201936067
abstract + abstract -

Context. The water snow line divides dry and icy solid material in protoplanetary disks. It has been thought to significantly affect planet formation at all stages. If dry particles break up more easily than icy ones, then the snow line causes a traffic jam because small grains drift inward at lower speeds than larger pebbles.
Aims: We aim to evaluate the effect of high dust concentrations around the snow line onto the gas dynamics.
Methods: Using numerical simulations, we modeled the global radial evolution of an axisymmetric protoplanetary disk. Our model includes particle growth, the evaporation and recondensation of water, and the back-reaction of dust onto the gas. The model takes into account the vertical distribution of dust particles.
Results: We find that the dust back-reaction can stop and even reverse the net flux of gas outside the snow line, decreasing the gas accretion rate onto the star to under 50% of its initial value. At the same time, the dust accumulates at the snow line, reaching dust-to-gas ratios of ɛ ≳ 0.8, and it delivers large amounts of water vapor towards the inner disk as the icy particles cross the snowline. However, the accumulation of dust at the snow line and the decrease in the gas accretion rate only take place if the global dust-to-gas ratio is high (ɛ0 ≳ 0.03), the viscous turbulence is low (αν ≲ 10-3), the disk is large enough (rc ≳ 100 au), and only during the early phases of the disk evolution (t ≲ 1 Myr). Otherwise the dust back-reaction fails to perturb the gas motion.

(77)Asteroseismology: Radial oscillations of neutron stars with realistic equation of state
  • V. Sagun,
  • G. Panotopoulos,
  • I. Lopes
Physical Review D (03/2020) doi:10.1103/PhysRevD.101.063025
abstract + abstract -

We study radial oscillations of non-rotating neutron stars (NSs) in four-dimensional general relativity. The interior of the NS was modeled within a recently proposed multicomponent realistic equation of state (EoS) with the induced surface tension (IST). In particular, we considered the IST EoS with two sets of model parameters, that both reproduce all the known properties of normal nuclear matter, give a high quality description of the proton flow constraint, hadron multiplicities created in nuclear-nuclear collisions, consistent with astrophysical observations and the observational data from the NS-NS merger. We computed the 12 lowest radial oscillation modes, their frequencies and corresponding eigenfunctions, as well as the large frequency separation for six selected fiducial NSs (with different radii and masses of 1.2, 1.5 and 1.9 solar masses) of the two distinct model sets. The calculated frequencies show their continuous growth with an increase of the NS central baryon density. Moreover, we found correlations between the behavior of the first eigenfunction calculated for the fundamental mode, the adiabatic index and the speed of sound profile, which could be used to probe the internal structure of NSs with the asteroseismology data.

(76)Toward Early-type Eclipsing Binaries as Extragalactic Milestones. II. NLTE Spectral Analysis and Stellar Parameters of the Detached O-type System OGLE-LMC-ECL-06782 in the LMC
  • Mónica Taormina,
  • Rolf-Peter Kudritzki,
  • Joachim Puls,
  • Bogumił Pilecki,
  • Eva Sextl
  • +3
  • G. Pietrzyński,
  • Miguel A. Urbaneja,
  • Wolfgang Gieren
  • (less)
The Astrophysical Journal (02/2020) doi:10.3847/1538-4357/ab6bd0
abstract + abstract -

We combine the NLTE spectral analysis of the detached O-type eclipsing binary OGLE-LMC-ECL-06782 with the analysis of the radial velocity curve and light curve to measure an independent distance to the Large Magellanic Cloud (LMC). In our spectral analysis we study composite spectra of the system at quadrature and use the information from radial velocity and light curve about stellar gravities, radii, and component flux ratio to derive effective temperature, reddening, extinction, and intrinsic surface brightness. We obtain a distance modulus to the LMC of m - M = 18.53 ± 0.04 mag. This value is 0.05 mag larger than the precision distance obtained recently from the analysis of a large sample of detached, long period late spectral type eclipsing binaries but agrees within the margin of the uncertainties. We also determine the surface brightnesses of the system components and find good agreement with the published surface brightness-color relationship. A comparison of the observed stellar parameters with the prediction of stellar evolution based on the MESA stellar evolution code shows reasonable agreement, but requires a reduction of the internal angular momentum transport to match the observed rotational velocities.

(75)Beauty at High Precision / Sensitivity
  • Chris Quigg
arXiv e-prints (02/2020) e-Print:2002.08292
abstract + abstract -

Origins of contemporary $B$-physics. Mesons with beauty and charm. Stable tetraquarks? Flavor and the problem of identity. Top matters. Electroweak symmetry breaking and the Higgs sector. Future instruments.

(74)Eclectic flavor groups
  • Hans Peter Nilles,
  • Saúl Ramos-Sánchez,
  • Patrick K. S. Vaudrevange
Journal of High Energy Physics (02/2020) doi:10.1007/JHEP02(2020)045
abstract + abstract -

The simultaneous study of top-down and bottom-up approaches to modular flavor symmetry leads necessarily to the concept of eclectic flavor groups. These are non-trivial products of modular and traditional flavor symmetries that exhibit the phenomenon of local flavor enhancement in moduli space. We develop methods to determine the eclectic flavor groups that can be consistently associated with a given traditional flavor symmetry. Applying these methods to a large family of prominent traditional flavor symmetries, we try to identify potential candidates for realistic eclectic flavor groups and show that they are relatively rare. Model building with finite modular flavor symmetries thus appears to be much more restrictive than previously thought.

(73)A Simple Unified Spectroscopic Indicator of Stellar Luminosity: The Extended Flux-weighted Gravity-Luminosity Relationship
  • Rolf-Peter Kudritzki,
  • Miguel A. Urbaneja,
  • Hans-Walter Rix
The Astrophysical Journal (02/2020) doi:10.3847/1538-4357/ab67c3
abstract + abstract -

We show that for a wide range of stellar masses, from 0.3 to 20 M, and for evolutionary phases from the main sequence to the beginning of the red giant stage, the stellar flux-weighted gravity, gF ≅ g/ ${T}_{\mathrm{eff}}^{4}$ , is tightly correlated with absolute bolometric magnitude ${M}_{\mathrm{bol}}$ . Such a correlation is predicted by stellar evolution theory. We confirm this relation observationally, using a sample of 445 stars with precise stellar parameters. It holds over 17 stellar magnitudes from ${M}_{\mathrm{bol}}$ = 9.0 to -8.0 mag with a scatter of 0.17 mag above ${M}_{\mathrm{bol}}$ = -3.0 and 0.29 mag below this value. We then test the relation with 2.2 million stars with 6.5 mag ≥ ${M}_{\mathrm{bol}}$ ≥ 0.5 mag, where "mass-produced" but robust $\mathrm{log}\,g$ , ${T}_{{\rm{e}}{\rm{f}}{\rm{f}}},$ and ${M}_{\mathrm{bol}}$ from LAMOST DR5 and Gaia DR2 are available. We find that the same relation holds with a scatter of ∼0.2 mag for single stars offering a simple spectroscopic distance estimate good to ∼10%.

(72)Large-scale Mixing in a Violent Oxygen-Neon Shell Merger Prior to a Core-collapse Supernova
  • Naveen Yadav,
  • Bernhard Müller,
  • Hans Thomas Janka,
  • Tobias Melson,
  • Alexander Heger
The Astrophysical Journal (02/2020) doi:10.3847/1538-4357/ab66bb
abstract + abstract -

We present a 7 minute long 4π-3D simulation of a shell merger event in a nonrotating 18.88 ${M}_{\odot }$ M ⊙ supernova progenitor before the onset of gravitational collapse. The key motivation is to capture the large-scale mixing and asymmetries in the wake of the shell merger before collapse using a self-consistent approach. The 4π geometry is crucial, as it allows us to follow the growth and evolution of convective modes on the largest possible scales. We find significant differences between the kinematic, thermodynamic, and chemical evolution of the 3D and 1D models. The 3D model shows vigorous convection leading to more efficient mixing of nuclear species. In the 3D case, the entire oxygen shell attains convective Mach numbers of ≈0.1, whereas in the 1D model, the convective velocities are much lower, and there is negligible overshooting across convective boundaries. In the 3D case, the convective eddies entrain nuclear species from the neon (and carbon) layers into the deeper part of the oxygen-burning shell, where they burn and power a violent convection phase with outflows. This is a prototypical model of a convective-reactive system. Due to the strong convection and resulting efficient mixing, the interface between the neon layer and the silicon-enriched oxygen layer disappears during the evolution, and silicon is mixed far out into the merged oxygen/neon shell. Neon entrained inward by convective downdrafts burns, resulting in lower neon mass in the 3D model compared to the 1D model at the time of collapse. In addition, the 3D model develops remarkable large-scale, large-amplitude asymmetries, which may have important implications for the impending gravitational collapse and subsequent explosion.