Cosmic-ray physics in the GeV-to-TeV energy range has entered a precision era thanks to recent data from space-based experiments. However, the poor knowledge of nuclear reactions, in particular for the production of antimatter and secondary nuclei, limits the information that can be extracted from these data, such as source properties, transport in the Galaxy and indirect searches for particle dark matter. The Cross-Section for Cosmic Rays at CERN workshop series has addressed the challenges encountered in the interpretation of high-precision cosmic-ray data, with the goal of strengthening emergent synergies and taking advantage of the complementarity and know-how in different communities, from theoretical and experimental astroparticle physics to high-energy and nuclear physics. In this paper, we present the outcomes of the third edition of the workshop that took place in 2024. We present the current state of cosmic-ray experiments and their perspectives, and provide a detailed road map to close the most urgent gaps in cross-section data, in order to efficiently progress on many open physics cases, which are motivated in the paper. Finally, with the aim of being as exhaustive as possible, this report touches several other fields ─ such as cosmogenic studies, space radiation protection and hadrontherapy ─ where overlapping and specific new cross-section measurements, as well as nuclear code improvement and benchmarking efforts, are also needed. We also briefly highlight further synergies between astroparticle and high-energy physics on the question of cross-sections.

Low-energy cosmic and solar radiation serves as a probe for investigations in astrophysics and heliophysics, and at the same time constitutes a risk to the spacecraft and crew of deep-space exploration missions. We present compact tracking calorimeters made from scintillating-plastic fibers and silicon photomultipliers that can determine the charge and energy of individual cosmic-ray nuclei with energies in the MeV-to-GeV range. Their comprehensive particle-identification capabilities allow to accurately determine the radiation exposure of astronauts and have potential applications in the indirect detection of dark matter.

A Very Large Telescope/MUSE population synthesis study of metallicities in the nuclear star-forming rings of four disk galaxies (NGC 613, NGC 1097, NGC 3351, NGC 7552) is presented. Disentangling the spectral contributions of young and old stellar populations, we find a large spread of ages and metallicities of the old stars in the nuclear rings. This indicates a persistent infall of metal-poor gas and ongoing episodic star formation over many Gyr. The young stars have metallicities a factor two to three higher than solar in all galaxies except NGC 3351, where the range is from half to twice solar. Previously reported detections of extremely metal-poor regions at young stellar age on the rings of these four galaxies are a methodological artifact of the average over all stars, young and old. In addition, it is important to include contributions of very young stars (<6 Myr) in this environment. For each of the four galaxies, the extinction maps generated through our population synthesis analysis provide support for the infall scenario. They reveal dust lanes along the leading edges of the stellar bars, indicating the flow of interstellar material toward the circumnuclear zone. Prominent stellar clusters show little extinction, most likely because of the onset of stellar winds. Inside and on the nuclear rings, regions that are largely free of extinction are detected.

At any given scale, 3 <inline-formula><tex-math>$\times$</tex-math></inline-formula> 2-point statistics extract only three numbers from the joint distribution of the cosmic matter density and galaxy density fluctuations: their variances and their covariance. It is well known that the full shape of the probability distribution function (PDF) of those fluctuations contains significantly more information than can be accessed through these three numbers. But the study of the PDF of cosmic density fluctuations in real observational data is still in its infancy. Here we present COSMOMENTUM, a public software toolkit for calculating theoretical predictions for the full shape of the joint distribution of a line-of-sight-projected tracer density and the gravitational lensing convergence. We demonstrate that an analysis of this full shape of the PDF can indeed disentangle complicated tracer bias and stochasticity relations from signatures of cosmic structure growth. Our paper also provides back-drop for an upcoming follow-up study, which prepares PDF analyses for application to observational data by incorporating the impact of realistic weak lensing systematics.

We combine spectral- and split representations to factorize multi-loop momentum space diagrams, in the Schwinger-Keldysh formulation for cosmological correlators, with massive scalars in the loop. This allows us to extend the resummation of loop contributions from flat to de Sitter space. Furthermore, in our split representation the signal part of the correlators can be identified directly on the integrand level from the spectral function. We apply this to describe the non-perturbative flow of the EFT background and the cosmological collider signals in a large-N model.

The Magellanic Clouds, the closest star-forming galaxies to the Milky Way, offer an excellent environment to study high-mass X-ray binaries. While the Small Magellanic Cloud has been thoroughly investigated with over 120 systems identified, the Large Magellanic Cloud has lacked a complete survey due to its large angular size. Most prior studies targeted central or high-star-formation regions. The SRG/eROSITA all-sky surveys now enable a comprehensive coverage of the LMC, particularly due to its close vicinity to the south ecliptic pole. This work aims to improve our understanding of the HMXB population in the LMC by building a flux-limited catalogue. This allows us to compare sample properties with those of HMXB populations in other nearby galaxies. Using detections during the first eROSITA all-sky survey, we cross-matched X-ray positions with optical and infrared catalogues to identify candidate HMXBs. We assigned flags based on multi-wavelength follow-up observations and archival data, using properties of known LMC HMXBs. These flags defined confidence classes for our candidates. We detect sources down to X-ray luminosities of a few $10^{34}$ erg s$^{-1}$, resulting in a catalogue of 53 objects, including 28 confirmed HMXBs and 21 new eROSITA detections. We identify several likely supergiant systems, including a candidate supergiant fast X-ray transient with phase-dependent flares. We find three Be stars with likely white dwarf companions. Two of the Be/WD candidates show steady luminosities across four eROSITA scans, unlike the post-nova states seen in the majority of previous Be/WD reports. Our catalogue is the first to cover the entire LMC since the ROSAT era, providing a basis for statistical population studies. Using the HMXB population, we estimate the LMC star-formation rate to be $(0.22^{+0.06}_{-0.07})$ M$_{\odot}$yr$^{-1}$, which is in agreement with other tracers.

Core-collapse supernovae (SNe) are sources of gravitational waves (GWs) produced by hydrodynamical instabilities and highly time-dependent anisotropies of the neutrino radiation. In this work we analyze both contributions to the GW signal for two state-of-the-art three-dimensional (3D) SN models computed with the Prometheus-Vertex neutrino-hydrodynamics code. In contrast to the far majority of models analyzed for GWs so far, our core-collapse simulations were started with 12.28 M_sun (18.88 M_sun) progenitors, whose final hour (7 min) of convective oxygen-shell burning was computed in 3D and featured a vigorous oxygen-neon shell merger. The corresponding large-scale asymmetries in the oxygen layer are conducive to buoyancy-aided neutrino-driven explosions. The models were continuously evolved in 3D from the pre-collapse evolution until 5.11 s (1.68 s) after the core bounce. The GW signals result from the well-known dynamical phenomena in the SN core such as prompt postshock convection, neutrino-driven convection, the standing accretion shock instability, proto-neutron star oscillations, and anisotropic ejecta expansion. They do not exhibit any new or specific features that can be unambiguously connected to the powerful pre-collapse activity in the progenitors, but we identify interesting differences compared to results in the literature. We also discuss measurement prospects by interferometers, confirming that GW signals from future Galactic SNe will be detectable with existing and next-generation experiments working in the frequency range f ~ 1-2000 Hz.

A system of classical interacting spins can develop collective instabilities which, in the nonlinear regime, mimic the motion of a gyroscopic pendulum. Known as the flavor pendulum, this behavior appears among the collective modes of a dense neutrino plasma after a strong reduction of phase space through symmetry assumptions. It has been identified in homogeneous slow and fast flavor systems and, most recently, in single-wave solutions of the fast system. We explain the reasons for its ubiquitous appearance. We show that a system of three classical spins must always be pendular, or only two in the presence of an external field. Furthermore, such a system always defines a continuum of vectors with time-independent length. If these are identified as interacting spins, they immediately lead to the continuum cases of slow and fast flavor pendula. As another new insight, any of these spins can be chosen as the pendulum, periodically exchanging flavor with the rest of the system.

Protoplanetary disk substructures are thought to play a crucial role in disk evolution and planet formation. Population studies of disks large-sample size surveys show that substructures, and their rapid formation, are needed to reproduce the observed spectral indices. Moreover, they enable the simultaneous reproduction of the observed spectral index and size-luminosity distributions. This study aims to investigate the necessity of substructures and predict their characteristics to reproduce gas-to-dust size ratios observed in the Lupus star-forming region. We performed a population synthesis study of gas and dust evolution in disks using a two-population model (two-pop-py) and the DustPy code. We considered the effects of viscous evolution, dust growth, fragmentation, transport, and external photoevaporation. The simulated population distributions were obtained by post-processing the resulting disk profiles of surface density, maximum grain size, and disk temperature. Although substructures help reduce the discrepancy between simulated and observed disk gas-to-dust size ratios; even when accounting for external photoevaporation, they do not fully resolve it. Only specific initial conditions in disks undergoing viscous evolution with external photoevaporation can reproduce the observations, highlighting a fine-tuning problem. While substructured disks reproduce dust size and spectral index, they tend to overestimate gas radii. The results ultimately highlight the main challenge of simultaneously reproducing gas and dust sizes. One possible explanation is that the outermost substructure is linked to the disk truncation radius, which determines the gas radius, or that substructures are frequent enough to always be near the gas outer radius.

We present a systematic study of the environments of 25 luminous quasars at $z > 6.5$ from the ASPIRE program. Using JWST/NIRCam WFSS data, we identified 487 galaxies at $5.3 \lesssim z \lesssim 7.0$ exhibiting [OIII] emission. Among these, 122 [OIII] emitters lie within $|∆v_{\rm los}| < 1000~{\rm km~s^{-1}}$ of the quasars, corresponding to a $\sim9.4$-fold enhancement relative to the average galaxy density at other redshifts. Furthermore, we identified 16 [CII]-emitting galaxies at the quasar redshifts from ALMA mosaic observations. A cross-correlation function (CCF) analysis between quasars and [OIII]+[CII] emitters yields a cross-correlation length of $r_0^{\rm QG} = 8.68^{+0.51}_{-0.55}~h^{-1}~\mathrm{cMpc}$ and a auto-correlation of $r_0^{\rm{QQ}}=15.76^{+2.48}_{-2.70}~h^{-1}~{\rm cMpc}$, indicating that $z \sim 7$ quasars reside in dark matter halos with $M_{\rm halo} = 10^{12.27^{+0.21}_{-0.26}}~M_\odot$. Notably, the number of [OIII]-emitting galaxies at quasar redshifts varies significantly from field to field, ranging from zero to twenty, highlighting a diverse quasar environment. Remarkably, seven quasars trace significant galaxy overdensities (i.e., protoclusters), with $δ_{\rm gal} > 5$ within a volume of $V \sim 500~{\rm cMpc^3}$. We also find that $|∆v_{\rm los}|$ increases rapidly toward smaller galaxy-quasar separations in protocluster fields, consistent with galaxy kinematics around extremely massive halos in cosmological simulations. By combining JWST and ALMA data, we reveal the complex and diverse environments of these early quasars, providing robust evidence that the earliest luminous quasars are effective tracers of galaxy overdensities, albeit with substantial field-to-field variation.

Although half-wave plates (HWPs) are becoming a popular choice of polarization modulators for cosmic microwave background (CMB) experiments, their non-idealities can introduce systematic effects that should be carefully characterized and mitigated. One possible mitigation strategy is to incorporate information about the non-idealities at the map-making level, which helps to reduce the HWP-induced distortions of the reconstructed CMB. Nevertheless, the non-idealities can only be known with finite precision. In this paper we investigate the consequences of discrepancies between their true frequency profiles and those assumed by the map-maker. We present an end-to-end framework, including a blind component-separation step, and use it to translate these discrepancies into a bias on the tensor-to-scalar ratio, $r$, for the LiteBIRD satellite mission. We subsequently derive realistic and conservative measurement requirements for accurately characterizing the HWP non-idealities to ensure they do not compromise LiteBIRD's ambitious scientific goals. We find that the obtained results are robust against sky models with varying complexity.

We introduce a simulation-based inference framework to constrain the origins of individual ultra-high-energy cosmic rays by combining realistic three-dimensional propagation modeling with Bayesian parameter estimation. Our method integrates CRPropa 3 simulations, including all relevant interactions and magnetic deflections in both Galactic and extragalactic fields, with approximate Bayesian computation to infer posterior distributions over key parameters such as source position, distance, energy, and magnetic field properties. This approach allows joint constraints from the observed energy and arrival direction to be applied simultaneously, naturally incorporating their correlations in addition to relevant modelling uncertainties. We demonstrate our method by applying it to the Amaterasu particle detected by the TA observatory, the second-highest-energy cosmic ray ever detected. The resulting posterior distributions quantify the regions of space consistent with its reconstructed properties under different energy and composition assumptions, revealing a broader set of nearby source candidates than found in previous analyses. This application highlights the framework's ability to translate individual ultra-high-energy cosmic-ray observations into directly interpretable source constraints and provides a foundation for future simulation-based analyses of cosmic rays at the highest energies.

We report the discovery of complex flaring activity from the galactic nucleus hosting the five-year-old tidal disruption event eRASSt J234402.9-352640 (J2344). With Einstein Probe and XMM-Newton observations, we detected highly structured soft X-ray variability. Through temporal decomposition of the XMM-Newton light curve and time-resolved spectral analysis, we identified broad, thermal flares recurring every $\sim$12 hours and lasting $\sim$2 hours, consistent with quasi-periodic eruptions (QPEs). Remarkably, these QPEs are accompanied by an unprecedented crest of hotter, shorter flares, each lasting between 5 and 30 minutes. These flares are predominantly found in the rising phases of the QPEs, although they also appear throughout the quiescence. These findings establish J2344 as a new member of the QPE emitter population and uncover a previously unobserved phenomenology that challenges current models of QPEs. In this letter, we present the phenomenological properties of this unique source and discuss possible interpretations within the framework of extreme-mass-ratio inspirals.

We report the multiwavelength properties of eROSITA Final Equatorial Depth Survey (eFEDS) J084222.9+001000 (hereafter ID830), a quasar at z = 3.4351, identified as the most X-ray luminous radio-loud quasar in the eFEDS field. ID830 shows a rest-frame 0.5─2 keV luminosity of <inline-formula> <mml:math><mml:mi>log</mml:mi><mml:mo>(</mml:mo><mml:msub><mml:mi>L</mml:mi><mml:mrow><mml:mn>0.5</mml:mn><mml:mo>−</mml:mo><mml:mn>2</mml:mn><mml:mspace></mml:mspace><mml:mi>keV</mml:mi></mml:mrow></mml:msub><mml:mo>/</mml:mo><mml:mi>erg</mml:mi><mml:mspace></mml:mspace><mml:msup><mml:mi>s</mml:mi><mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup><mml:mo>)</mml:mo><mml:mo>=</mml:mo><mml:mn>46.20</mml:mn><mml:mo>±</mml:mo><mml:mn>0.12</mml:mn></mml:math> </inline-formula>, with a steep X-ray photon index (Γ = 2.43 ± 0.21), and a significant radio counterpart detected with the Very Large Array FIRST 1.4 GHz and Very Large Array Sky Survey 3 GHz bands. The rest-frame UV to optical spectra from Sloan Digital Sky Survey and Subaru/MOIRCS J band show a dust-reddened quasar feature with A_V = 0.39 ± 0.08 mag, and the expected bolometric active galactic nuclei luminosity from the dust-extinction-corrected UV luminosity reaches L_bol,3000Å = (7.62 ± 0.31) × 10⁴⁶ erg s⁻¹. We estimate a black hole mass of M_BH = (4.40 ± 0.72) × 10⁸ M_⊙ based on the Mg IIλ2800 emission-line width, and Eddington ratios from the dust-extinction-corrected UV continuum luminosity and X-ray luminosity that reach λ_Edd,UV = 1.44 ± 0.24 and λ_Edd,X = 12.8 ± 3.9, respectively, both indicating super-Eddington accretion. ID830 shows a high ratio of UV to X-ray luminosities, α_OX = −1.20 ± 0.07 (or α_OX = −1.42 ± 0.07 after correcting for jet-linked X-ray excess), higher than quasars and little red dots in the super-Eddington phase with similar UV luminosities, with α_OX < −1.8. Such a high α_OX suggests the coexistence of a prominent radio jet and X-ray corona in this high-Eddington-accretion phase. We propose that ID830 may be in a transitional phase after an accretion burst, evolving from a super-Eddington to a sub-Eddington state, which could naturally describe the high α_OX.

Axions and axion-like particles are compelling candidates for ultralight bosonic dark matter, forming coherent oscillating fields that can be probed by experiments known as haloscopes. A broad range of haloscope concepts has been developed, including resonant cavity haloscopes, lumped-element circuit detectors, and spin-based experiments, each sensitive to different axion couplings and mass ranges. Rather than attempting an exhaustive survey of all existing approaches, this comparative review provides a unified framework for the major haloscope classes, establishing a common language for the descriptions of signal generation, noise properties, data analysis, and scanning strategies. Key properties of ultralight bosonic dark matter relevant for detection are summarized first, including coherence time, spectral linewidth, and stochasticity under the standard halo model. The discussion then compares cavity, Earth-scale, lumped-element, and spin haloscopes, focusing on expected signal shapes, dominant noise sources, and statistical frameworks for axion searches. Particular emphasis is placed on consistent definitions of signal-to-noise ratio and on how detector bandwidth, axion coherence, and noise characteristics determine optimal scan strategies. By systematically comparing operating principles and performance metrics across these detector families, this framework clarifies shared concepts as well as the essential differences that govern sensitivity in different mass and coupling regimes. The resulting perspective synthesizes current search methodologies and offers guidance for optimizing future haloscope experiments.

Recent theoretical work has revealed that basic observables of quantum field theory in de Sitter space, known as in-in or cosmological correlators, exhibit surprisingly simple mathematical structure reminiscent of scattering amplitudes in flat space. For many theories, this simplicity can be made manifest using a set of ``cosmological dressing rules'' which uplift flat-space Feynman diagrams to in-in correlators in de Sitter space by attaching auxiliary propagators to the interaction vertices. In this paper, we show that discontinuities of cosmological correlators with respect to internal energy variables can be obtained by applying auxiliary propagators to unitarity cuts of flat space Feynman diagrams. Moreover, discontinuities with respect to external energy variables can be obtained by cutting auxiliary propagators attached to Feynman diagrams. This observation in turn implies highly non-trivial constraints on cosmological correlators in the form of simple sum rules. We illustrate these ideas in a number of examples at tree-level and 1-loop for conformally coupled scalar theories, although they hold more generally. Finally, we show how to reconstruct cosmological correlators from their discontinuities using dispersion relations, providing a powerful new approach to computing cosmological observables by systematically reconstructing them from data uplifted from flat space.

Principled Bayesian inference of galaxy properties has not previously been performed for wide-area weak lensing surveys with millions of sources. We address this gap by applying the pop-cosmos generative model to perform spectral energy distribution (SED) fitting for 4 million KiDS-1000 galaxies. Calibrated on deep COSMOS2020 photometric data, pop-cosmos specifies a physically-motivated prior over the galaxy population up to $z \simeq 6$ in stellar population synthesis (SPS) parameter space. Using the Speculator SPS emulator with GPU-accelerated MCMC sampling, we perform full posterior inference at 6.5 GPU seconds per galaxy, obtaining joint constraints on galaxy redshifts and physical properties. We validate photometric redshifts against $\sim\!185,\!000$ KiDS galaxies cross-matched to DESI DR1 spectroscopic samples, achieving low bias ($3\times10^{-3}$), scatter ($σ_{\mathrm{MAD}}=0.04$), and outlier fraction (3.7%) for the Bright Galaxy Survey, with comparable performance (bias $3\times10^{-2}$, $σ_{\mathrm{MAD}}=0.05$, 1.3% outliers) for luminous red galaxies (LRGs). Within the LRG sample, we identify massive, dusty, star-forming contaminants at $z \simeq 0.4$ satisfying standard colour selections for quenched populations. We infer trends in stellar mass, star formation, metallicity, and dust across five tomographic redshift bins consistent with established scaling relations. Using specific star formation rate constraints, we identify $\sim$10% of KiDS-1000 galaxies as quenched, versus 37% implied by conservative colour cuts. This enables the construction of weak lensing samples defined by physical properties while mitigating intrinsic alignment systematics and preserving statistical power. Our analysis validates pop-cosmos out-of-sample, establishing it as a scaleable approach for galaxy evolution and cosmological analyses in photometric surveys.

Feynman integrals whose associated geometries extend beyond the Riemann sphere, such as elliptic curves and Calabi-Yau varieties, are increasingly relevant in modern precision calculations. They arise not only in collider cross-section calculations, but also in the post-Minkowskian expansion of gravitational-wave scattering. A powerful approach to compute integrals of this type is via differential equations, particularly when cast in a canonical form, which simplifies their $\varepsilon$-expansion and makes analytic properties manifest. In these proceedings, we will present a method to systematically construct canonical differential equations even for integrals that evaluate beyond multiple polylogarithms. The discussion is kept as light as possible, focusing on the two-loop sunrise integral, deferring the technical details to the original publications.

In both observed and simulated galaxies, disk morphologies become more prevalent at higher masses and lower redshifts. To elucidate the physical origin of this trend, we develop a simple analytical model in which galaxy morphology is governed by the competition between rotational support and turbulence in a gravitational potential of a dark matter halo and the galaxy itself, and a disk forms when the potential steepens due to the accumulation of baryons in the halo center. The minimum galaxy mass required for this transition decreases with an increasing dark matter contribution within the galaxy, making more concentrated halos more prone to forming disks. Our model predicts that galaxy sizes behave qualitatively differently before and after disk formation: after disks form, sizes are governed by the halo spin, in agreement with classical models, whereas before disk formation, sizes are larger and set by the scale on which turbulent motions, which dominate over rotation, can be contained. We validate our model against the results of the TNG50 cosmological simulation and, despite the simplicity of the model, find remarkable agreement. In particular, our model explains the increase with redshift in the critical halo mass for disk formation, reported in both simulations and observations, as a consequence of the evolution of the halo mass-concentration and baryonic mass-halo mass relations. This redshift trend therefore supports the recent proposal that it is the steepening of the gravitational potential that causes disk formation, while other effects discussed in the literature, such as potential deepening and hot gaseous halo formation, can still play important roles in the transition from early turbulent to dynamically cold disks.

Exomoons around free-floating planets (FFPs) can survive their host planet's ejection. Such ejections can increase their orbital eccentricity, providing significant tidal heating in the absence of any stellar energy source. Previous studies suggested that liquid water could exist on such moons under thick CO$_2$-dominated atmospheres, but these models faced challenges with CO$_2$ condensation and atmospheric collapse, particularly in the high-pressure regimes that favoured long-term habitability. To address this, we employ a self-consistent model, including radiative transfer and equilibrium chemistry with condensation, to simulate a more stable hydrogen-dominated atmosphere for a range of initial chemical compositions, including C, O, and N. We find that such atmospheres can effectively trap heat via collision-induced absorption of H$_2$, maintaining surface temperatures suitable for liquid water for time-scales of up to 4.3 Gyr, depending on the surface pressure, while not prone to condensation-induced collapse. Wet-dry cycling caused by the strong tides together with the alkalinity of dissolved NH$_3$ could create favourable conditions for RNA polymerisation and thus support the emergence of life.

We study the correlation functions of a conformally coupled $ϕ^4$-interacting theory in AdS$_3$ and its dual CFT$_2$. The one-loop diagram is not expressible in terms of known transcendental functions, but is shown to be expressible as an infinite sum of previously well-studied tree-level diagrams, and we compute this sum using several number-theoretic conjectures. This enables us to extract recursively, the analytic expressions of anomalous dimensions of all dual double-trace operators. In the $s$-channel various consistency checks were performed against established bootstrap method, while our results in the $t$- and $u$-channel are not available in any previous literature to our knowledge.

At any given scale, 3 <inline-formula><tex-math>$\times$</tex-math></inline-formula> 2-point statistics extract only three numbers from the joint distribution of the cosmic matter density and galaxy density fluctuations: their variances and their covariance. It is well known that the full shape of the probability distribution function (PDF) of those fluctuations contains significantly more information than can be accessed through these three numbers. But the study of the PDF of cosmic density fluctuations in real observational data is still in its infancy. Here we present COSMOMENTUM, a public software toolkit for calculating theoretical predictions for the full shape of the joint distribution of a line-of-sight-projected tracer density and the gravitational lensing convergence. We demonstrate that an analysis of this full shape of the PDF can indeed disentangle complicated tracer bias and stochasticity relations from signatures of cosmic structure growth. Our paper also provides back-drop for an upcoming follow-up study, which prepares PDF analyses for application to observational data by incorporating the impact of realistic weak lensing systematics.

The R3B experiment at FAIR studies nuclear reactions using high-energy radioactive beams. One key detector in R3B is the CALIFA calorimeter consisting of 2544 CsI(Tl) scintillator crystals designed to detect light charged particles and gamma rays with an energy resolution in the per cent range after Doppler correction. Precise cluster reconstruction from sparse hit patterns is a crucial requirement. Standard algorithms typically use fixed cluster sizes or geometric thresholds. To enhance performance, advanced machine learning techniques such as agglomerative clustering were implemented to use the full multi-dimensional parameter space including geometry, energy and time of individual interactions. An Edge Detection Neural Network exhibited significant differences. This study, based on Geant4 simulations, demonstrates improvements in cluster reconstruction efficiency of more than 30%, showcasing the potential of machine learning in nuclear physics experiments.

For cellular functions such as division and polarization, protein pattern formation driven by NTPase cycles is a central spatial control strategy. Operating far from equilibrium, no general theory links microscopic reaction networks and parameters to the pattern type and dynamics in these protein systems. Here we discover a generic mechanism giving rise to an effective interfacial tension organizing the macroscopic structure of non-equilibrium steady-state patterns. Namely, maintaining protein-density interfaces by cyclic protein attachment and detachment produces curvature-dependent protein redistribution, which straightens the interface. We develop a non-equilibrium Neumann angle law and Plateau vertex conditions for interface junctions and mesh patterns, thus introducing the concepts of 'Turing mixtures' and 'Turing foams'. In contrast to liquid foams and mixtures, these non-equilibrium patterns can select an intrinsic wavelength by interrupting an equilibrium-like coarsening process. Data from in vitro experiments with the Escherichia coli Min protein system verify the vertex conditions and support the wavelength dynamics. Our study shows how interface laws with correspondence to thermodynamic relations can arise from distinct physical processes in active systems. It allows the design of specific pattern morphologies with potential applications as spatial control strategies in synthetic cells.

We introduce a new photometric catalog of RR Lyrae variables (RRLs, $\sim$300,000) mainly based on data available in public datasets. We also present the largest and most homogeneous spectroscopic dataset of RRLs and Blue Horizontal Branch [BHB] stars ever collected. This includes radial velocity measurements ($\sim$16,000) and iron abundances ($Δ$S method for 8,140 RRLs, plus 547 from literature). Elemental abundances based on high-resolution spectra are provided for 487 RRLs and 64 BHB stars. We identified candidate RRLs associated to the main Galactic components and their iron distribution function (IDF) becomes more metal-rich when moving from the Halo ([Fe/H]=-1.56) to the Thick (TCD; [Fe/H]=-1.47) and Thin (TND; [Fe/H]=-0.73) disk. Furthermore, Halo RRLs and RRLs in retrograde orbits are $α$-enhanced ([$α$/Fe]=0.27, $σ$=0.18), while TCD RRLs are either $α$-enhanced ([Fe/H]$\le$-1.0) or $α$-poor ([Fe/H]$>$-1.0), and TND RRLs are mainly $α$-poor ([$α$/Fe]=-0.01, $σ$=0.20). We also identified RRLs associated to the main stellar streams (Gaia-Sausage-Enceladus [GSE]; Sequoia, Helmi, Sagittarius) and we found that their IDFs are quite similar to Halo RRLs. However, GSE RRLs lack the metal-poor/metal-rich tails and their $α$-element distribution is quite compact. The iron radial gradient in Galactocentric distance for TND, TCD and Halo RRLs is negative and it decreases from -0.026, to -0.010, and to -0.002 dex/kpc. The iron radial gradient based on dry Halo (Halo without substructures) RRLs is, within the errors, equal to the global Halo. We also found a strong similarity between iron and [$α$/Fe] radial gradients of Milky Way RRLs and M31 globular clusters throughout the full range of galactocentric distances covered by the two samples.

We present a detailed multiwavelength afterglow study of the short gamma-ray burst (GRB) GRB 250704B, extensively monitored in optical and near-infrared bands. Its afterglow displays an unusually long duration plateau followed by an achromatic break and a steep decline, deviating from canonical GRB afterglows. While long plateaus are often explained by central engine activity, we find that for GRB 250704B an energy injection model requires unreasonable parameters. The afterglow is better explained by an off-axis power-law structured jet with a narrow core (θ_c ≍ 0<inline-formula> <mml:math><mml:mover><mml:mrow><mml:mo>.</mml:mo></mml:mrow><mml:mrow><mml:mtext>°</mml:mtext></mml:mrow></mml:mover></mml:math> </inline-formula>7) viewed at a modest angle (θ_v ≍ 1<inline-formula> <mml:math><mml:mover><mml:mrow><mml:mo>.</mml:mo></mml:mrow><mml:mrow><mml:mtext>°</mml:mtext></mml:mrow></mml:mover></mml:math> </inline-formula>9). A comparison with GRB 170817A shows that both events are consistent with the off-axis structured jet scenario, where the shape of the light curve is governed primarily by the geometry of the jet and the viewing angle rather than the energetics, microphysical parameters, or external density. Our results underscore the importance of incorporating the jet structure in GRB modeling.

We perform the first dedicated comparison of five hadronic codes (AM³, ATHEνA, B13, LeHa-Paris, and LeHaMoC) that have been extensively used in modeling the spectral energy distribution (SED) of jetted active galactic nuclei. The purpose of this comparison is to identify the sources of systematic errors (e.g., implementation method of proton─photon interactions) and to quantify the expected dispersion in numerical SED models computed with the five codes. The outputs from the codes are first tested in synchrotron self-Compton scenarios that are the simplest blazar emission models used in the literature. We then compare the injection rates and spectra of secondary particles produced in pure hadronic cases with monoenergetic and power-law protons interacting on blackbody and power-law photon fields. We finally compare the photon SEDs and the neutrino spectra for realistic proton-synchrotron and leptohadronic blazar models. We find that the codes are in excellent agreement with respect to the spectral shape of the photons and neutrinos. There is a remaining spread in the overall normalization that we quantify, at its maximum, at the level of ±40%. This value should be used as an additional, conservative, systematic uncertainty term when comparing numerical simulations and observations.

We study parameter estimation for the transport coefficients of the quark-gluon plasma by differentiating open-quantum-system-based Monte Carlo simulations of quarkonium suppression. The underlying simulator requires solving a Lindblad equation in a large Hilbert space, which makes parameter estimation computationally expensive. We approach the problem using gradient-based optimization. Specifically, we apply the score-function gradient estimator to differentiate through discrete jump sampling in the Monte Carlo wave-function algorithm used to solve the Lindblad equation. The resulting stochastic gradient estimator exhibits sufficiently low variance and can still be estimated in an embarrassingly parallel manner, enabling efficient scaling of the simulations. We implement this gradient estimator in the existing open-source quarkonium suppression code QTraj. To demonstrate its utility for parameter estimation, we infer the two transport coefficients $\hatκ$ and $\hatγ$ using gradient-based optimization on synthetic nuclear modification factor data.

Young binary stars with discs provide unique laboratories for studying the earliest stages of planet formation in star-forming environments. The detection of substructure in discs around Class I protostars challenges current models of disc evolution, and suggests that planets may form earlier than previously expected (< 1 Myr). In the context of the FAUST Large Program, we present observations of the circumbinary disc (CBD) around the young binary system L1551 IRS 5. The CBD exhibits two prominent over-densities in the continuum emission at the edge of the cavity, with the northern over-density being about 20% brighter than the southern one. By analysing the disc morphology and kinematics of L1551 IRS 5, we delineate dynamical constraints on the binary's orbital parameters. Additionally, we present 3D hydrodynamical models of the CBD to predict both the dust and the gas surface densities. Then, we compare the resulting synthetic observations with ALMA observations of the continuum emission at 1.3 mm and the C¹⁸O line emission. Our analysis suggests that the density enhancements observed with ALMA in L1551 IRS 5 can be caused by interactions between the binary stars and the CBD, leading to dust concentration within the disc. We conclude that the observed over-density corresponds to a location where solids could potentially grow in size under favourable conditions.

We explore the formation of intermediate mass black holes (IMBHs), potential seeds for supermassive black holes (SMBHs), via runaway stellar collisions for a wide range of star cluster (surface) densities ($4\times10^3 M_\odot$ pc$^{-2} \lesssim Σ_\mathrm{h}$ $\lesssim 4\times10^6 M_\odot$ pc$^{-2}$) and metallicities ($0.01 Z_\odot \lesssim Z \lesssim 1.0 Z_\odot)$. Our sample of isolated $(>1400)$ and hierarchical ($30$) simulations of young, massive star clusters with up to $N=1.8\times10^6$ stars includes collisional stellar dynamics, stellar evolution, and post-Newtonian equations of motion for black holes using the BIFROST code. High stellar wind rates suppress IMBH formation at high metallicities $(Z \gtrsim 0.2 Z_\odot)$ and low collision rates prevent their formation at low densities ($Σ_\mathrm{h} \lesssim 3\times10^4 M_\odot$ pc$^{-2}$). The assumptions about stellar wind loss rates strongly affect the maximum final IMBH masses $(M_\bullet \sim 6000 M_\odot$ vs. $25000 M_\odot$). The total stellar mass loss from collisions and collisionally boosted winds before $t=3$ Myr can together reach up to 5-10% of the final cluster mass. We present fitting formulae for IMBH masses as a function of host star cluster $Σ_\mathrm{h}$ and Z, and formulate a model for the cosmic IMBH formation rate density. Depending on the cluster birth densities, the IMBH formation rates peak at $z\sim2$-$4$ at up to $\sim10^{-7}$ yr$^{-1}$cMpc$^{-3}$. As more than 50% form below $z\lesssim1.5$-$3$, the model challenges a view in which all local IMBHs are failed early Universe SMBH seeds.

We investigate whether photoevaporation alone can open and sustain gaps in protoplanetary discs by coupling the evolving disc structure with the photoevaporative flow in two dimensional radiation hydrodynamical simulations. Our results show that once a density depression forms, the local mass-loss rate decreases sharply, suppressing further gap deepening. Viscous inflow and radial mass transport along the disc surface act to partially refill the depleted region, preventing complete clearing. The resulting configuration is a persistent, partially depleted zone whose evolution is largely insensitive to the initial disc morphology. This behaviour challenges the standard paradigm that photoevaporation efficiently carves clean inner cavities and directly produces transition discs. However, the pressure maximum at the outer edge of the depression may still trap dust grains, giving rise to transition disc like observational signatures. We also present a first-order prescription to approximate this behaviour in one dimensional disc evolution models, suitable for use in planet formation and population synthesis studies. Although the prescription improves upon static mass-loss treatments, it remains approximate, underscoring the need for further multidimensional simulations and parameter-space exploration to derive robust recipes for global disc and planet population models.

Active galactic nuclei (AGNs) drive powerful, multiphase outflows that are thought to play a key role in galaxy evolution. The hot, shocked phase of these outflows (<inline-formula><tex-math>$T{\gtrsim }10^{6}{\rm {\ K}}$</tex-math></inline-formula>) is expected to dominate the energy content, but is challenging to observe due to its long cooling time and low emissivity. The cool phase (<inline-formula><tex-math>$T{\lesssim }10^{4}{\rm {\ K}}$</tex-math></inline-formula>) is easier to detect observationally, but it traces a less energetic outflow component. In prior simulations of the interaction between an energy-driven AGN outflow and a clumpy ISM, we found that mixing between hot wind and cool ISM clouds produces a new, highly radiative, phase at <inline-formula><tex-math>$T{\approx }10^{6-7}{\rm {\ K}}$</tex-math></inline-formula> which fuels the formation of a long-lived (<inline-formula><tex-math>$\ge 5\ \rm {Myr}$</tex-math></inline-formula>) cool outflow. We investigate the X-ray emission generated by thermal Bremsstrahlung and high-ionization metal line emission in this mixing phase, finding that it could contribute significantly to the X-ray output of the outflow. This mixing-induced X-ray emission is strongest in the part of the outflow propagating equatorially through the disc, and is extended on scales of <inline-formula><tex-math>$D\simeq 3\!-\!4\ \rm {kpc}$</tex-math></inline-formula>. For quasar luminosities of <inline-formula><tex-math>$L_{\rm {AGN}}{\simeq } 10^{45-46}\rm {\ erg\ s^{-1}}$</tex-math></inline-formula>, the resulting X-ray luminosity is equivalent to that expected from star formation rates <inline-formula><tex-math>$\rm {SFR}\simeq 10\!-\!200\ \rm {M_\odot \ yr^{-1}}$</tex-math></inline-formula>, showing that it could be an important source of soft X-rays in AGN host galaxies. Our results suggest that this extended emission could be resolvable in local quasars (<inline-formula><tex-math>$z\lesssim 0.11$</tex-math></inline-formula>) using high spatial-resolution X-ray observatories such as Chandra, or proposed missions such as AXIS and Lynx.

Changing-state active galactic nuclei (CSAGNs) exhibit rapid variability, with mass accretion rates that can change by several orders of magnitude in a few years. This provides us with a unique opportunity to study the evolution of the inner accretion flow almost in real time. Here, we used over 1000 observations to study the broadband X-ray spectra of a sample of five CSAGNs, spanning three orders of magnitude in Eddington ratio ($λ_{\rm Edd}$), using phenomenological models to trace the evolution of key spectral components. We derive several fundamental parameters, such as the photon index, soft excess strength, reflection strength, and luminosities of the soft excess and primary continuum. We find that the soft excess and primary continuum emissions show a very strong positive correlation ($p \ll 10^{-10}$), suggesting a common physical origin. The soft excess strength does not show any dependency on the reflection parameter, suggesting that in these objects the soft excess is not dominated by a blurred ionized reflection process. On the other hand, the strength of the soft excess is found to be strongly positively correlated with the Eddington ratio ($p \ll 10^{-10}$), and we find that the soft excess vanishes below $\log λ_{\rm Edd} \sim -2.5$. Moreover, we find a clear `V'-shaped relation for $Γ-λ_{\rm Edd}$, with a break at $\log λ_{\rm Edd} = -2.47 \pm 0.09$. Our findings indicate a change in the geometry of the inner accretion flow at low Eddington ratios, and that the soft excess is primarily produced via warm Comptonization.

Tidal features provide signatures of recent galaxy mergers, offering insights into the role of mergers in galaxy evolution. The Vera C. Rubin Observatory's upcoming Legacy Survey of Space and Time (LSST) will allow for an unprecedented study of tidal features around millions of galaxies. We use mock images of galaxies at <inline-formula><tex-math>$z\sim 0$</tex-math></inline-formula> (<inline-formula><tex-math>$z\sim 0.2$</tex-math></inline-formula> for NEWHORIZON) from NEWHORIZON, EAGLE, ILLUSTRISTNG, and MAGNETICUM PATHFINDER simulations to predict the properties of tidal features in LSST-like images. We find that tidal features are more prevalent around blue galaxies with intrinsic colours <inline-formula><tex-math>$(g-i)\le 0.5$</tex-math></inline-formula>, compared to redder ones, at fixed stellar mass. This trend correlates with elevated specific star formation rates (<inline-formula><tex-math>$\mathrm{sSFR}>10^{-10}\mathrm{\:yr}^{-1}$</tex-math></inline-formula>), suggesting that merger-induced star formation contributes to the bluer colours. Tidal feature hosts in the red sequence appear to exhibit colour profiles offset to bluer colours for galaxies with stellar masses <inline-formula><tex-math>$10^{10}< M_{\star \mathrm{,\:30\:pkpc}}/\mathrm{M}_\odot < 10^{11}$</tex-math></inline-formula>, similarly blue cloud tidal feature host galaxies appear to have their colour profiles offset to bluer colours for <inline-formula><tex-math>$10^{9.5}< M_{\star \mathrm{,\:30\:pkpc}}/\mathrm{M}_\odot < 10^{10.5}$</tex-math></inline-formula>. However, the differences in colour profiles in either the red sequence or the blue cloud are not statistically robust and larger samples are needed to test if these differences are real. The predictions across the simulations are quantitatively distinct; therefore, LSST observations will allow us to further constrain the differences between different subgrid physics models.

An asteroseismic analysis has revealed a magnetic field in the deep interior of a slowly rotating main-sequence F star KIC 9244992, which was observed by the Kepler spacecraft for 4 yr. The star shows clear asymmetry of frequency splittings of high-order dipolar gravity modes, which cannot be explained by rotation alone, but are fully consistent with a model with rotation, a magnetic field, and a discontinuous structure (glitch). Careful examination of the frequency dependence of the asymmetry allows us to put constraints on not only the radial component of the magnetic field but also its azimuthal (toroidal) component. The lower bounds of the root mean squares of the radial and azimuthal components in the radiative region within 50 per cent in radius, which have the highest sensitivity in the layers just outside the convective core with a steep gradient of chemical compositions, are estimated to be <inline-formula><tex-math>${\mathsf {B}_{\text{r}}^{\text{min}}}=3.5\pm 0.1\, \text{kG}$</tex-math></inline-formula> and <inline-formula><tex-math>${\mathsf {B}_{\phi }^{\text{min}}}= 92 \pm 7\, \text{kG}$</tex-math></inline-formula>, respectively. The much stronger azimuthal component than the radial one is consistent with the significant contribution of the differential rotation, although the star has almost uniform rotation at present. The estimated field strengths are too strong to be explained by dynamo mechanisms in the radiative zone associated with the magnetic Tayler instability. The aspherical glitch is found to be located in the innermost radiative layers where there is a steep gradient of chemical composition. The first detection of magnetic fields in the deep interior of a main-sequence star sheds new light on the problem of stellar magnetism, for which there remain many uncertainties.

In this study, we perform a comparative analysis of the properties of the H II regions located in different areas of barred galaxies, with the aim of investigating the impact of bars on the physical properties of the ionized gas. Based on integral field spectroscopy data for 17 barred galaxies covering approximately the central <inline-formula><tex-math>$6\times 6$</tex-math></inline-formula> kpc, we detect a total of 2200 <inline-formula><tex-math>${\mathrm H\, {\small II}}$</tex-math></inline-formula> regions, of which 331 are located within the nuclear disc (also known as circumnuclear regions), 661 in the bar region, and 1208 in the disc. Among the physical properties of the <inline-formula><tex-math>${\mathrm H\, {\small II}}$</tex-math></inline-formula> regions, we explore the O/H and N/O abundances, H<inline-formula><tex-math>$\alpha$</tex-math></inline-formula> luminosity, dust extinction, electron density, and H<inline-formula><tex-math>$\alpha$</tex-math></inline-formula> equivalent width. We find clear differences in the properties of the <inline-formula><tex-math>${\rm H\, {\small II}}$</tex-math></inline-formula> regions between the nuclear disc, the bar, and the disc, that could be explained by an enhancement in the molecular gas concentration in the central parts driven by bar-induced gas flows. As this gas is channelled towards the galaxy centre, the most extreme values in the analysed properties are found for the circumnuclear <inline-formula><tex-math>${\rm H\, {\small II}}$</tex-math></inline-formula> regions. Unlike the bar strength, galaxy mass does seem to affect the properties of the <inline-formula><tex-math>${\rm H\, {\small II}}$</tex-math></inline-formula> regions, with massive galaxies presenting higher values in most of the properties, possibly due to the increased amount of gas in these systems. This study provides evidence that the bar-driven redistribution of material within the galaxy inner parts causes significant differences in the <inline-formula><tex-math>${\rm H\, {\small II}}$</tex-math></inline-formula> region properties depending on their location within the galaxies.

Context. Cosmic voids are a promising probe of cosmology for spectroscopic galaxy surveys due to their unique response to cosmological parameters. Their combination with other probes promises to break parameter degeneracies. Aims. Due to simplifying assumptions, analytical models for void statistics represent only a subset of the full void population. We present a set of neural-based emulators for void summary statistics of watershed voids, which retain more information about the full void population than simplified analytical models. Methods. We built emulators for the void size function and void density profiles traced by the halo number density using the QUIJOTE suite of simulations that spans a wide range of the Λ cold dark matter (ΛCDM) parameter space. The emulators replace the computation of these statistics from computationally expensive cosmological simulations. We demonstrate the cosmological constraining power of voids using our emulators, which offer orders-of-magnitude acceleration in parameter estimation, capture more cosmological information compared to analytical models, and produce more realistic posteriors compared to Fisher forecasts. Results. In this QUIJOTE setup, we recover the parameters Ω_m and σ₈ to within 14.4% and 8.4% accuracy, respectively, using void density profiles. Incorporating additional information from the void size function improves the accuracy for σ₈ to 6.8%. We demonstrate the robustness of our approach with respect to two important variables in the underlying simulations: the resolution and the inclusion of baryons. We find that our pipeline is robust to variations in resolution, and we show that the posteriors derived from the emulated void statistics are unaffected by the inclusion of baryons in the Magneticum hydrodynamic simulations. This opens up the possibility of a baryon-independent probe of the large-scale structure.

We aim to evaluate how well the variation of small-scale magnetic fields on the stellar surface can be monitored with time-series observations. Further, we aim to establish to what extent the measured total unsigned magnetic field traces other activity indicators. We measured the total unsigned magnetic field on four young, stars using Zeeman splitting of magnetically sensitive spectral lines from high-resolution spectra obtained with the spectropolarimeters ESPaDOnS at CFHT and NARVAL at TBL. We then characterised the magnetic field variations using both sinusoidal variation and Lomb-Scargle periodograms. We evaluated how the rotational variation of the total unsigned magnetic field strength correlates with the activity indicators S-index, H$α$-index, Ca IRT-index, and the large-scale magnetic field obtained from ZDI maps obtained in earlier studies. We find clear signals of rotational modulation of the total magnetic field on HIP 76768 and tentative detection on Mel 25-5. This is supported both by the sinusoidal fitting and the periodogram. For the other stars, we find no modulation signals of the total magnetic field. We find positive correlations between the total magnetic field and activity indices on all four stars, indicating that indirect magnetic activity indicators trace the underlying magnetic field variability. However, comparing the activity-magnetic field relationship between the stars in our sample shows a significant deviation between activity level and measured magnetic field strength. Small-scale magnetic field variability can be traced using the Zeeman effect on magnetically sensitive lines, provided that the star is sufficiently active. It is also possible to self-consistently recover rotational periods from such measurements. The primary limit for the detection of magnetic field variations is the precision of Zeeman broadening and intensification measurements.

The initial mass function (IMF) is a cornerstone of star formation studies, yet its universality remains debated. We investigate the IMF in the young massive cluster RCW 36, located in the Vela Molecular Ridge and comparable to the Orion Nebula Cluster in stellar density. Our goal is to build the most complete census of RCW 36 and derive its first IMF and star-to-brown-dwarf (BD) ratio. We combine new GLAO observations from HAWK-I/VLT with archival data (2MASS, SOFI/NTT) and Gaia DR3 kinematics. Photometric accuracy and source extraction were improved using \textsc{DeNeb}, a deep-learning algorithm that removes complex nebular emission. Membership probabilities were assigned via color-magnitude diagram comparisons with a control field, and stellar masses were estimated using model isochrones. We find a revised distance of $954\pm40\,$pc and determine the IMF down to $\sim0.03\,M_{\odot}$, described by a broken power law ($dN/dM\propto M^{-α}$) with $α=1.62\pm0.03$ for $0.20$-$20\,M_{\odot}$ and $α=0.46\pm0.14$ for $0.03$-$0.20\,M_{\odot}$. The star-BD ratio is $2$-$5$, consistent with other Galactic clusters. Lastly, through a study of the differences in the IMF within and outside $0.2\,$pc and the cumulative mass distributions for low-mass and intermediate to high-mass sources, we also detected signs of possible mass segregation within RCW 36, which should be primordial. RCW 36 shares many characteristics with other young massive clusters, such as a shallower than Salpeter high-mass slope and the possibility of mass segregation. The flatter lower-mass regime of the IMF is similar to most Galactic clusters. The star-BD ratio is also in line with the observed values in other clusters, independent of their inherent properties.

We present the equation of state for two classes of new ultralight particles, a scalar field coupling to electrons and a light <inline-formula><tex-math>$\mathbb {Z}_\mathcal {N}$</tex-math></inline-formula> QCD axion field coupling to nucleons. Both are potential candidates for dark matter. Using the scalar modified equations of state, we calculate models for white dwarf stars and compare their radii and masses with observed mass─radius data. The comparison results in stringent constraints on the masses of the particles and the coupling parameters. For a wide range of particle masses and coupling parameters, constraints from the white dwarf equation of state surpass existing limits, outperforming also dedicated laboratory searches. The remarkable accuracy of modern white-dwarf mass─radius relation data, exemplified by Sirius B, now allows stringent tests of dense-matter physics and constraints on new particle scenarios.

This proceedings paper briefly reviews the status of direct experimental probes into the neutrino-mass scale, with an emphasis on recent results from the KATRIN experiment.

The calculation of precise predictions for Higgs decays is a necessary ingredient for determining Higgs properties at the LHC and future colliders. We compute all two- and three-body Higgs decays at next-to-leading order (NLO) in both QCD and electroweak interactions using the dimension-6 Standard Model Effective Field Theory (SMEFT). Results for four-body Higgs decays that are accurate to NLO QCD/electroweak order in the SMEFT are obtained using the narrow width approximation. Our results are contained in a flexible Monte Carlo program, NEWiSH, that is publicly available and we illustrate the impact of the NLO electroweak corrections for HL-LHC, Tera-Z, and Higgstrahlung projections.

We derive a general expression for the resummation of rapidity distributions for processes with a colorless final state, such as Drell-Yan or Higgs production, in the limit in which the center-of-mass energy goes on threshold, but with fixed rapidity of the Higgs or gauge boson in the partonic center-of-mass frame. The result is obtained by suitably generalizing the renormalization-group based approach to threshold resummation previously pursued by us. The ensuing expression is valid to all logarithmic orders but the resummation coefficients must be determined by comparing to fixed order results. We perform this comparison for the Drell-Yan process using the fixed-order next-to-next-to-leading (NNLO) result, thereby determining resummation coefficients up to next-to-next-to-leading logarithmic (NNLL) accuracy, for the quark-antiquark coefficient function in the quark nonsinglet channel. We provide a translation to direct QCD of a result for this resummation previously obtained using SCET methods, and we show that it agrees with our own.

Chemical reaction networks are central to all chemical models. Each rate coefficient has an associated uncertainty, which is generally not taken into account when calculating the chemistry. We performed the first uncertainty analysis of a chemical model of C- and O-rich asymptotic giant branch (AGB) outflows using the RATE22 reaction network. Quantifying the error on the model predictions enables us to determine the need for adding complexity to the model. Using a Monte Carlo sampling method, we quantified the impact of the uncertainties on the chemical kinetic data on the predicted fractional abundances and column densities. The errors are caused by a complex interplay of reactions forming and destroying each species. Parent species show an error on their envelope sizes, which is not caused by the uncertainty on their photodissociation rate, but rather the chemistry reforming the parent after its photodissociation. Using photodissociation models to estimate the envelope size might be an oversimplification. The error on the CO envelope impacts retrieved mass-loss rates by up to a factor of two. For daughter species, the error on the peak fractional abundance ranges from a factor of a few to three orders of magnitude, and is on average about 10 per cent of its value. This error is positively correlated with the error on the column density. The standard model suffices for many species, e.g. the radial distribution of cyanopolyynes and hydrocarbon radicals around IRC +10216. However, including spherical asymmetries, dust-gas chemistry, and photochemistry induced by a close-by stellar companion are still necessary to explain certain observations.

We present an implementation of radiative transfer with flux-limited diffusion (FLD) for the moving-mesh code AREPO and use the method in a physical model for the formation of protostars with non-ideal radiation-magnetohydrodynamics (RMHD). We follow previous work in splitting the additional terms to the hydrodynamical equations arising from the inclusion of radiation into terms to be integrated explicitly and implicitly, as the diffusion and coupling terms would impose very restrictive time-step criteria. We validate the scheme with standard test problems for radiation diffusion, matter─gas coupling, and radiative shocks from the literature. Our implementation is compatible with local time-stepping, which often presents problems for implicit schemes, and we found very good agreement with results obtained with global time-steps. We present an example application of the new implementation to the collapse of a <inline-formula><tex-math>$1\, {\rm M}_\odot$</tex-math></inline-formula> molecular cloud core to a second Larson core modelled with radiation non-ideal magnetohydrodynamics. A high-velocity jet with v<inline-formula><tex-math>$_{\rm rad}> 10\, {\rm km\, s^{-1}}$</tex-math></inline-formula> is self-consistently launched from the second core, nested within the first core, which produces a lower-velocity magnetorotational outflow. We observe magnetic field amplification up to more than <inline-formula><tex-math>$\vert \mathbf {B}\vert _{\rm max}>10^5$</tex-math></inline-formula> G in the second core, which is surrounded by a small (<inline-formula><tex-math>$< 0.5$</tex-math></inline-formula> au) disc. This application demonstrates the robustness of our scheme in multiscale and high-resolution simulations on arbitrary meshes and, as such, the model can be readily used for further simulations of protostar formation at high resolution.

We provide an explicit construction of a manifestly duality invariant, interacting deformation of Maxwell theory in four dimensions in terms of mutually local, but interacting 1- and 3-forms. Interestingly, our theory is formulated directly as a BRST quantized gauge theory, while the underlying gauge invariant Lagrangian before gauge fixing is obscured. Furthermore, the underlying gauge invariance is based on an associative, rather than a Lie symmetry.

The tidal disruption of planets by their host stars represents a growing area of interest in transient astronomy, offering insights into the final stages of planetary system evolution. We model the hydrodynamic evolution and predict the multi-wavelength observational signatures of planetary TDEs around a solar-mass host, focusing on Jupiter-like and Neptune-like progenitors and examining how different eccentricities of the planet's pre-disruption orbit shape the morphology and emission of the tidal debris.We perform 2D hydrodynamic simulations using the FARGO3D code to model the formation and viscous evolution of the resulting debris disk. We employ a viscous alpha-disk prescription and include a time-dependent energy equation to compute the disk's effective temperature and subsequently derive the bolometric and multi-band photometric light curves.Our simulations show that planetary TDEs produce a diverse range of luminous transients. A Jupiter-like planet disrupted from a circular orbit at the Roche limit generates a transient peaking at $L_{bol} \approx 10^{38}$ erg s$^{-1}$ after a 12-day rise. In contrast, the same planet on an eccentric orbit (e=0.5) produces a transient of comparable peak luminosity but on a much shorter timescale, peaking in only 1 day and followed by a highly volatile light curve. We find that the effect of eccentricity is not universal, as it accelerates the event for Jupiter but delays it for Neptune. A robust "bluer-when-brighter" colour evolution is a common feature as the disk cools over its multi-year lifetime. The strong dependence of light curve morphology on the initial orbit and progenitor mass makes these events powerful diagnostics. This framework is crucial for identifying planetary TDEs in time-domain surveys.

The first four all-sky surveys with eROSITA the soft X-ray instrument on board the Spektrum-Roentgen-Gamma (SRG) satellite revealed a new X-ray source, eRASSU J012422.9-724248, in the Magellanic Bridge, near the Eastern Wing of the Small Magellanic Cloud (SMC). We performed a broadband timing and spectral analysis using the optical and X-ray data of eRASSU J012422.9-724248. Using the X-ray observations with eROSITA, Swift, NuSTAR and optical data from the optical Gravitational Lensing Experiment (OGLE) and the Las Cumbres Observatory (LCO), we confirm the nature of eRASSU J012422.9-724248 as a Be/X-ray binary (BeXRB) pulsar in the Magellanic bridge. The position is coincident with that of an early-type star (OGLE ID SMC732.10.7). We detect the spin period at 341.71 s in NuSTAR data and infer a period of 63.65 days from the 15 year monitoring with OGLE, that we interpret as the orbital period of the system. A tentative CRSF at ~12.3 keV is identified in NuSTAR spectra with ~1.8-sigma. The source appears to show a persistent X-ray luminosity and an optical magnitude transition on the long timescale. We propose eRASSU J012422.9-724248 is a new member of the class of persistent BeXRBs.

We study the sensitivity of past and future stopped-pion experiments to light, invisible dark sector particles produced in exotic pion decays. We consider two-body decays involving sterile neutrinos, $π^+ \to \ell^+ N$, as well as three-body decays $π^+ \to \ell^+ ν_\ell X$, with $X$ an invisible scalar, axion-like particle, or dark vector. We recast existing limits from the PIENU experiment and project the reach of the planned PIONEER experiment using detailed simulations based on the current detector design. We find that PIONEER can improve bounds on exotic pion branching ratios by at least one order of magnitude below current limits. We compare the projected sensitivities with complementary constraints from lepton anomalous magnetic moments, mono-photon searches, and beam-dump experiments, identifying weak-violating axion-like particles as a particularly well-motivated benchmark. Our results establish PIONEER as a powerful and complementary probe of light, invisible dark sectors.

A dense neutrino plasma can exhibit collective flavor evolution caused by neutrino--neutrino refraction. Recently, a new class of exact nonlinear inhomogeneous solutions was discovered: single-wave (SW) solutions of the fast flavor system. The key property is that the flavor occupation numbers remain homogeneous, whereas the field of flavor coherence varies spatially with a single wave vector. The equations of motion for this structure resemble those of a collection of classical spins, in analogy with the homogeneous slow and fast flavor cases. In contrast, the SW system is not integrable (it does not possess Gaudin invariants) so that, while two-beam pendulum solutions are inevitable, they do not extend to a multi-angle system. We develop a taxonomy of all known nonlinear collective flavor solutions, explaining the overlap between categories and their differences.

We consider Loryons, particles beyond the Standard Model that receive a significant fraction of their masses from electroweak symmetry breaking, in the context of a two Higgs doublet model. Using scalar Loryons in the the $[1,1]$, $[1,3]$ (as well as the equivalent $[3,1]$) and the $[2,2]$ representations of the custodial $SU(2)_L \times SU(2)_R$ global symmetry as benchmarks, we study the constraints on the Loryon parameter space, focusing on unitarity, Higgs decay observables, and the absence of Loryon vacuum expectation values. We find that while neutral singlet Loryons remain viable for masses up to 700 GeV, representations containing charged scalars are severely constrained by LHC data, particularly as the fraction of mass generated by symmetry breaking increases.

The AMBER experiment at CERN will measure the proton’s charge radius via muon-proton elastic scattering at high projectile energies and small momentum transfers to help to resolve the so-called proton radius puzzle, i.e., the discrepancy between charge radii measured with different experimental techniques. The core setup at AMBER consists of a hydrogen-filled time projection chamber (TPC). Tracking detectors upstream and downstream of the TPC measure the trajectories of the incoming and outgoing muons to determine their scattering angles. To resolve pile-up hits in the tracking detectors, we are constructing four high-granularity hodoscopes from 500-<math altimg="si1.svg" display="inline" id="d1e204"><mrow><mi mathvariant="normal">μ</mi><mi mathvariant="normal">m</mi></mrow></math> scintillating-plastic fibers and arrays of silicon photomultipliers. In this contribution, we present the design of the scintillating-fiber hodoscopes and first results of test-beam measurements with scaled-down prototypes. We will particularly emphasize how we managed to design detectors with a low material budget.