# Non-thermal Dark Matter from Modified Early Matter Domination

## TL;DR

This paper investigates how multiple fields during early matter domination influence non-thermal dark matter production, allowing for higher dark matter masses and lower reheating temperatures than in standard models.

## Contribution

It introduces the impact of multiple fields on dark matter production during early matter domination, expanding the viable parameter space for dark matter mass and reheating temperature.

## Key findings

- Subdominant second fields can significantly increase universe temperature during early matter domination.
- Enhanced temperature effects allow for PeV-scale dark matter with reheating temperatures below 10 GeV.
- The model broadens the parameter space for dark matter relic abundance calculations.

## Abstract

Thermal freeze-out or freeze-in during a period of early matter domination can give rise to the correct dark matter abundance for $\langle \sigma_{\rm ann} v \rangle_{\rm f} < 3 \times 10^{-26}$ cm$^3$ s$^{-1}$. In the standard scenario, a single field that behaves like matter drives the early matter dominated era. However, in realistic models, this epoch may involve more than one field. In this paper, we study the effect of such a modification on the production of dark matter during early matter domination. We show that even a subdominant second field that decays much faster than the dominant one can considerably enhance the temperature of the universe during an early matter-dominated phase. This in turn affects dark matter production via freeze-out/in and opens up the allowed parameter space toward significantly larger dark matter masses. As a result, one can comfortably obtain the correct relic abundance for PeV-scale dark matter for reheating temperatures at or below 10 GeV.