Thermal Dark Matter and the impact of low temperature reheating

by Dr Kuldeep Deka (New York U., Abu Dhabi)

Tuesday 20 Aug 2024, 16:00 → 17:30 Asia/Seoul

Room 1423 (KIAS)

Title: Thermal Dark Matter and the impact of low temperature reheating

Speaker: Dr. Kuldeep Deka (New York U., Abu Dhabi)

Abstract: Despite decades of experimental efforts, the nature of dark matter (DM) remains elusive. The hypothesis that DM consists of weakly interacting massive particles (WIMPs) in thermal equilibrium with the standard model (SM) has been a major focus, yet no definitive evidence supports WIMP DM. This has spurred interest in other thermal production mechanisms, such as strongly interacting massive particles (SIMPs), elastically decoupling relics (ELDERs), and cannibals, where DM self-interactions are crucial. We examine the production of these thermal DM candidates during cosmic reheating, using a general parametrization for the scaling of inflaton energy density and SM temperature. We analyze the requirements for kinetic and chemical DM freeze-out in a model-independent manner. For each mechanism, we identify up to two solutions that match the observed DM relic density for a given reheating scenario and DM mass. In a simple model where DM interacts through contact interactions, we find that low-temperature reheating allows for a wider range of couplings and larger masses than in the usual instantaneous high-temperature reheating. WIMP masses can reach up to $10^{14}$ GeV, while SIMP and ELDER masses can reach up to $10^{13}$ GeV. However, cannibal solutions are still not allowed, consistent with high-temperature reheating scenarios. Current experiments already constrain this parameter space, and next-generation experiments could further probe these scenarios.