Modifying dark matter indirect detection signals by thermal effects at freeze-out

TL;DR

This paper extends the Standard Model with scalar singlets and a fermion dark matter candidate, showing how thermal effects at freeze-out influence indirect detection signals and predicting gravitational wave signatures from a first-order electroweak phase transition.

Contribution

It introduces a new model where dark matter freeze-out and indirect detection signals are decoupled, and predicts associated gravitational wave signatures.

Findings

Dark matter annihilation channels differ between freeze-out and indirect detection.

The model predicts a distinct indirect detection cross-section.

Gravitational wave signals are associated with the electroweak phase transition.

Abstract

We present an extension of the Standard Model, containing a fermion dark matter candidate and two real scalar singlets, where the observed dark matter abundance is produced via freeze-out before the electroweak phase transition. We show that in this case the dark matter annihilation channels determining its freeze-out are different from those producing indirect detection signal. We present a benchmark model where the indirect annihilation cross-section differs from the freeze-out one. The model also has a gravitational wave signature due to the first order electroweak phase transition.