Dark Matter from Exponential Growth

TL;DR

This paper introduces a new mechanism for dark matter production where DM particles exponentially grow by transforming heat bath particles, expanding the possible parameter space for explaining observed dark matter abundance.

Contribution

It presents a novel exponential growth mechanism for dark matter production from a thermal bath, complementing existing freeze-in and freeze-out models.

Findings

Mechanism allows exponential growth of DM from small initial abundance.

Expands parameter space for dark matter models.

Discusses observational prospects for the new scenario.

Abstract

We propose a novel mechanism for the production of dark matter (DM) from a thermal bath, based on the idea that DM particles $\chi$ can transform heat bath particles $\psi$: $\chi \psi \rightarrow \chi \chi$. For a small initial abundance of $\chi$ this leads to an exponential growth of the DM number density, in close analogy to other familiar exponential growth processes in nature. We demonstrate that this mechanism complements freeze-in and freeze-out production in a generic way, opening new parameter space to explain the observed DM abundance, and we discuss observational prospects for such scenarios.