Conveners
Cosmology & Fundamental Physics
- Krzysztof Turzyński (University of Warsaw)
to be added
We performed the first simulations of accretion onto the compact objects in the Reissner-Nordström (RN) space-time. The results could not be more different for the two cases. For a black hole, just as in the familiar Kerr case, matter overflowing the cusp plunges into the black hole horizon. For the naked singularity, the accreting matter forms an inner structure of toroidal topology and...
The significant tensions in constraints on the Hubble constant ($𝐻_0$) and clustering amplitude ( $𝑆_8$) between early- and late-universe observations challenge key assumptions of the LCDM cosmological model. One of these assumptions is the presence of cold dark matter, a yet-to-be-detected non-relativistic particle with minimal interaction with the Standard Model that dominates the mass...
We will discuss interpretation of the nHz stochastic gravitational wave background (SGWB) seen by NANOGrav and other Pulsar Timing Array (PTA) Collaborations in the context of supermassive black hole (SMBH) binaries. The frequency spectrum of this stochastic background is predicted more precisely than its amplitude. We will discuss how Dark Matter friction can suppress the spectrum around nHz...
The detection of gravitational waves (GWs) has led to a deeper understanding of binaries of ordinary astrophysical objects, including neutron stars and black holes. We point out that binary systems may also exist in a dark sector with astrophysical-mass macroscopic dark matter. These “dark binaries”, when coupled to an additional attractive long-range dark force, may generate a stochastic...
We study the thermal freeze-out of two-component dark matter (DM). The freeze-out in a multicomponent dark sector can be more complex and richer than the canonical single-component WIMP DM. This is owing to the relevance of processes of conversions, co-annihilations, co-scatterings, decays and self-scatterings in addition to those of annihilations and elastic scatterings, which can affect the...
The origin and nature of neutrino mass remain one of the most intriguing puzzles in particle physics. To account for the small but nonzero neutrino masses, we propose a hybrid mass-generation mechanism that integrates the canonical seesaw mechanism with radiative neutrino mass generation. This framework is formulated within a non-Abelian discrete flavor symmetry, whose spontaneous breaking not...
