# Multiscatter capture of superheavy dark matter by Pop. III stars

## TL;DR

This paper investigates how superheavy dark matter particles can be captured by Population III stars through multiscatter interactions, potentially affecting star evolution and providing a novel way to constrain dark matter properties.

## Contribution

It introduces an analytical formalism for multiscatter capture of superheavy dark matter by Pop. III stars and explores its implications for star evolution and dark matter constraints.

## Key findings

- Upper bounds on dark matter capture rates by Pop. III stars.
- Potential influence of dark matter annihilation heat on star evolution.
- Constraints on Pop. III star masses based on dark matter interactions.

## Abstract

If captured by the gravitational field of stars or other compact objects, dark matter can self-annihilate and produce a potentially detectable particle flux. In the case of superheavy dark matter ($ m_{X} \gtrsim 10^{8} GeV $), a large number of scattering events with nuclei inside stars are necessary to slow down the dark matter particles below the escape velocity of the stars, at which point the Dark Matter (DM) particle becomes trapped, or captured. Using the recently developed analytical formalism for multiscatter capture, combined with the latest results on the constraints of dark-matter-baryon scattering cross-section, we calculate upper bounds on the capture rates for superheavy dark matter particles by the first (Pop. III) stars. Assuming that a non-zero fraction of the products of captured superheavy dark matter (SHDM) annihilations can be trapped and thermalized inside the star we find that this additional heat source could influence the evolutionary phase of Pop. III stars. Moreover, requiring that Pop. III stars shine with sub-Eddington luminosity, we find upper bounds on the masses of the Pop. III stars. This implies a DM dependent cutoff on the initial mass function (IMF) of Pop. III stars, thus opening up the intriguing possibility of constraining DM properties using the IMF of extremely metal-poor stars.