Conveners
Cosmology II
- Keisuke Harigaya (IAS)
The discrepancy in measurements of the Hubble constant $H_0$ indicates new physics in dark energy, dark matter, or both. Drawing inspiration from string theory, where the dilaton interacts with the other moduli fields to accommodate the Agrawal-Obied-Vafa proposal of fading dark matter, we explore possible solutions to overcome the $H_0$ problem.
In the 5-dimensional braneworld cosmology, the Friedmann equation of our 4-dimensional universe on a brane is modified at high temperatures while the standard Big Bang cosmology is reproduced at low temperatures. Based on two well-known scenarios, the Randall-Sundrum and Gauss-Bonnet braneworld cosmologies, we investigate the braneworld cosmological effect on the relic density of a non-thermal...
Non-trivial dynamics within the dark sector can give rise to a complicated, non-thermal dark-matter phase-space distribution, which in turn can affect the shape of the matter power spectrum. In this talk, we examine the extent to which one can address the archaeological "inverse" problem of deciphering the properties of the underlying dark sector from features imprinted in the matter power...
Particle-physics processes within the dark sector could leave imprints on the dark-matter phase-space distribution, and therefore influence the way in which structure forms in the early universe. In a recent paper [arXiv:2001.02193], we proposed a procedure for reconstructing the dark-matter phase-space distribution from the shape of the matter power spectrum. In this talk, we demonstrate how...
In this talk I will introduce a new paradigm for the thermal production of dark matter in the early Universe, in which dark-matter particles acquire their mass and freeze out spontaneously from the thermal bath after a dark phase transition takes place. The decoupling arises because the dark-matter particles become suddenly nonrelativistic and not because of any decay channel becoming...
Lyman-alpha forest observations require the mass of warm dark matter (DM) particles to be greater than a few keV. We calculate how this bound is modified if the warm dark matter particles are also self-interacting. We use a linear perturbation evolution code, which we wrote ourselves, to determine the growth of the initial perturbations in the early universe for warm self-interacting dark...
Light dark sector particles, especially bosons if coupled to the inflaton can be copiously produced during (p)reheating epoch courtesy to Bose enhancement. In many particle physics scenarios such particles are often invoked to resolve tensions with cosmologicalbounds from Big Bang Nucleosynthesis (BBN), Cosmic Microwave Background (CMB) and Large Scale Structure (LSS). We will discuss two...
