Skip navigation.

Institute for the Physics and Mathematics of the UniverseWPI

IPMU Seminar

Date: September 9, 2008, 15:30 - 16:30
Place: Seminar Room at IPMU Prefab. B, Kashiwa Campus of the University of Tokyo
Speaker: Mitsuru Kakizaki (Bonn University)
Title: Abundance of Thermal Relics in Non-standard Cosmological Scenarios [PDF]
Abstract: We investigate the relic density of non-relativistic long-lived or stable particles in non-standard cosmological scenarios. We derive approximate solution for the relic density which accurately reproduce numerical results when full thermal equilibrium is not achieved. Assuming that thermally produced WIMPs account for the observed dark matter energy density, we obtain the lower bound on the reheat temperature, and constrain possible modifications of the Hubble expansion rate. We also propose a new ansatz for the thermally-averaged annihilation cross section of relic particles that decouple semi-relativistically, and derive an approximate analytic solution for their abundance. Some applications of such semi-relativistically decoupled relics are discussed