Changes in Dark Matter Properties After Freeze-Out

TL;DR

This paper explores how dark matter properties can change after freeze-out due to a scalar phase transition, potentially explaining discrepancies in observed dark matter abundance and cosmic ray data.

Contribution

It introduces a model where dark matter properties evolve post-freeze-out via a scalar phase transition, offering new explanations for observed anomalies.

Findings

Dark matter properties can differ before and after a scalar phase transition.

The mechanism can reconcile collider and astrophysical measurements of dark matter.

Potential to explain the PAMELA cosmic ray excess.

Abstract

The properties of the dark matter that determine its thermal relic abundance can be very different from the dark matter properties today. We investigate this possibility by coupling a dark matter sector to a scalar that undergoes a phase transition after the dark matter freezes out. If the value of Omega_DM h^2 calculated from parameters measured at colliders and by direct and indirect detection experiments does not match the astrophysically observed value, a novel cosmology of this type could provide the explanation. This mechanism also has the potential to account for the "boost factor" required to explain the PAMELA data.