Precise dark matter relic abundance in decoupled sectors

TL;DR

This paper refines the calculation of dark matter relic abundance in decoupled sectors, showing that the required annihilation cross-section can significantly differ from standard estimates, affecting search strategies.

Contribution

It extends the standard freeze-out framework to decoupled sectors and provides precise cross-section calculations, revealing substantial deviations from canonical values.

Findings

The required annihilation cross-section can differ by orders of magnitude from standard estimates.

Precise calculations impact interpretation of dark matter search results.

Decoupled sectors can produce relic abundances with different thermal histories.

Abstract

Dark matter (DM) as a thermal relic of the primordial plasma is increasingly pressured by direct and indirect searches, while the same production mechanism in a decoupled sector is much less constrained. We extend the standard treatment of the freeze-out process to such scenarios and perform precision calculations of the annihilation cross-section required to match the observed DM abundance. We demonstrate that the difference to the canonical value of this 'thermal cross-section' is generally sizeable, and can reach orders of magnitude. Our results directly impact the interpretation of DM searches in hidden sector scenarios.