Dark Matter and Graviton Freeze-in from Warm Inflation

by Dr Barmak Shams Es Haghi (University of Texas, Austin)

Tuesday Apr 15, 2025, 3:00 PM → 4:00 PM Pacific/Honolulu

Room 420 (Watanabe Hall)

In this talk, I will present a novel perspective on the role of inflation in the production of Dark Matter (DM). Specifically, I will explore the DM production during Warm Inflation via ultraviolet Freeze-In (WIFI). After a brief review of DM production from a thermal bath, I will discuss the possibility of having a radiation bath during the inflationary phase; the so-called Warm Inflation (WI). Then I will demonstrate that in a WI setting the persistent thermal bath, sustained by the dissipative interactions with the inflaton field, can source a sizable DM abundance via the non-renormalizable interactions that connect the DM with the bath. Compared to the (conventional) radiation-dominated UV freeze-in scenario for the same reheating temperature, the resulting DM yield in WIFI is always enhanced. As I will show,  for a sufficiently large mass dimension of the operator, the entirety of the DM abundance of the Universe can be created during the inflationary phase. I will also discuss the inevitable production of hot gravitons during warm inflation and highlight the prospects for their detection.

Barmak-Hawaii-Aprill2025.pdf