# Exponential Enhancement of Dark Matter Freezeout Abundance

### Submission summary

 As Contributors: Bibhushan Shakya Arxiv Link: https://arxiv.org/abs/2210.01215v1 (pdf) Date submitted: 2022-10-05 10:30 Submitted by: Shakya, Bibhushan Submitted to: SciPost Physics Proceedings Proceedings issue: 14th International Conference on Identification of Dark Matter Academic field: Physics Specialties: High-Energy Physics - Phenomenology Approaches: Theoretical, Phenomenological

### Abstract

A novel paradigm for thermal dark matter (DM), termed "bouncing dark matter", is presented. In canonical thermal DM scenarios, the DM abundance falls exponentially as the temperature drops below the mass of DM, until thermal freezeout occurs. This note explores a broader class of thermal DM models that are exceptions to this rule, where the DM abundance can deviate from the exponentially falling curve, and even rise exponentially, while in thermal equilibrium. Such scenarios can feature present day DM annihilation cross sections much larger than the canonical thermal target, improving the prospects for indirect detection of DM annihilation signals.

###### Current status:
Editor-in-charge assigned

### Submission & Refereeing History

Submission 2210.01215v1 on 5 October 2022

## Reports on this Submission

### Strengths

1. The manuscript studies a novel mechanism of dark matter freeze-out, by introducing certain mass hierarchy among several (meta-)stable dark particles.

2. It clearly illustrates the effects of such mass hierarchy in dark matter freeze-out, especially it requires a slightly larger dark matter annihilation cross section than the standard case.

None.

### Report

The submission is clearly written, discussing a novel dark matter freeze-out mechanism. Thus I recommend its publication in SciPost Physics Proceedings, with a minor change.

### Requested changes

I strongly suggest that the author mention the effect of other processes, e.g. $\chi + \phi_2 \to \phi_1 + \phi_2$, as this puzzles me a lot during reading this proceeding. It seems to forbid $Y_{\chi} > Y_{\phi_2}$, if I understand their original paper correctly.

• validity: high
• significance: good
• originality: high
• clarity: top
• formatting: excellent
• grammar: excellent