APEC Seminar (Astronomy - Particle Physics - Experimental Physics - Cosmology)

Speaker: Julia Harz (Johannes Gutenberg University Mainz)
Title: Dark Matter Production at Finite Temperature
Date (JST): Wed, Feb 25, 2026, 13:30 - 15:00
Place: Seminar Room A
Abstract:
Finite-temperature effects can play a relevant role in the production of dark matter, depending on the underlying mechanism. I will begin with a brief overview of the well-established freeze-out scenario and explain why thermal corrections are typically subleading in this framework. The main focus of this talk will be on finite-temperature effects in the freeze-in mechanism. After motivating freeze-in and emphasizing its connection to collider searches and cosmology, I will review the current state of the art and discuss conceptual limitations of existing approaches. I will then present a first-principles calculation of scalar dark matter production in the freeze-in regime and compare our results with previous ones. I will conclude by showing that our framework further resolves unphysical, negative production rates at low momenta, as previously reported for axion-like particle production from Abelian gauge bosons, where the low-momentum spectrum plays a crucial role in structure-formation constraints.