Abstract: Many of the long-standing mysteries in theoretical physics today are, in one way or another, related to gravity. This fact is a very powerful motivation for trying to improve our knowledge on gravitational interactions and plausible extensions of general relativity, in particular to understand their consistency with basic physical principles like unitarity, locality and causality. In this talk I will show how such fundamental principles lead to positivity constraints on scattering amplitudes in…

Abstract: Heavy sterile neutrinos (aka neutral heavy leptons) represent one of the most popular exotic particle extensions to the Standard Model (SM). With their role in explaining the masses of the light SM neutrinos and potentially the existence of matter via a Leptogenesis mechanism, they are being searched for in a large number of experiments. One of the most important processes in this regard is neutrinoless double beta (0nubb) decay, which generally probes the presence of lepton number violating…

Abstract: Wakefield accelerators driven by intense laser pulses can now produce GeV electron bunches and broadband multi-keV X-rays with femtosecond duration. By using the multiple-beam capabilities available at high-intensity laser facilities, these beams are powerful tools for exploring extreme conditions that are found in astrophysical environments and can be created in highly transient experiments in the laboratory. Conditions that can be studied include the high temperatures and pressures in…

Abstract: Recent studies of the quark-matter equation of state constrained by neutron-star mass-radius measurements strongly supports a smooth, continuous crossover from nuclear matter to the possible quark matter at several times nuclear matter densities.  Aside from favoring quark-hadron continuity, the required stiffness of the equation of state also indicates strong diquark pairing and vector repulsion that are significantly stronger than the traditionally considered Fierz-transformed four-quark…

Abstract: The first Science Week of the ORIGINS Cluster will take place from December 2 to 5, 2019 in the New Seminar Room (1.1.18ab) at the Max-Planck Institute for extraterrestrial Physics. Cluster scientists and invited guests will present their current research work in the fields of astrophysics, cosmology, particle, nuclear physics and biophysics. The Science Week is an interdisciplinary event and directed to all scientists who want to gain insight into the current state of all Cluster research…

Abstract: We announce that the 17th Russbach School on Nuclear Astrophysics will again take place at the village of Rußbach am Paß Gschütt, southeast of Salzburg, Austria. The school dates will be from March 15 (arrival and registration) to March 21 (departure) 2020. This school belongs to the European Network of Nuclear Astrophysics Schools (ENNAS). We shall limit the number of participants to about 60 to ensure a convivial atmosphere, and the possibility to share dinners between all participants. In…

Abstract: The study of the dynamic Universe on all astronomical scales allows us to pinpoint the underlying physical processes that not only lead to the formation of stars and planets from the turbulent interstellar medium, but also determine the structure of the Universe on the largest observable scales.  The meeting is organised in honour of Professor Andi Burkert and to celebrate his 60th birthday. The workshop highlights the various dynamical processes covered by Andi's work and brings together…