Lepton collider as a window to reheating via freezing in dark matter detection. Part II

TL;DR

This paper explores how collider signals, specifically mono-photon and dilepton events at the ILC, can reveal details about dark matter production during reheating, linking collider physics with early universe dynamics.

Contribution

It demonstrates that collider signals can probe UV freeze-in dark matter production during reheating, especially in bosonic scenarios, connecting collider data with post-inflationary cosmology.

Findings

Mono-photon signals can indicate dark matter production during reheating.

Bosonic reheating scenarios can produce the correct dark matter abundance.

Collider signals correlate with post-inflationary universe dynamics.

Abstract

Dark matter (DM) genesis via Ultraviolet (UV) freeze-in embeds the seed of reheating temperature and dynamics in its relic density. Thus, discovery of such a DM candidate can possibly open the window for post-inflationary dynamics. However, there are several challenges in this exercise, as freezing-in DM possesses feeble interaction with the visible sector and therefore very low production cross-section at the collider. We show that mono-photon (and dilepton) signal at the ILC, arising from DM effective operators connected to the SM field strength tensors, can still warrant a signal discovery. We study both the scalar and fermionic DM production during reheating via UV freeze-in, when the inflaton oscillates at the bottom of a general monomial potential. Interestingly, we see, right DM abundance can be achieved only in the case of bosonic reheating scenario, satisfying bounds from big bang nucleosynthesis (BBN). This provides a unique correlation between collider signal and the post-inflationary dynamics of the Universe within single-field inflationary models.