Gravitationally Induced Particle Production and its Impact on the WIMP Abundance

TL;DR

This paper explores how gravitationally induced particle production affects the abundance of WIMP dark matter, using a new kinetic equation approach and comparing results with standard models.

Contribution

It introduces a novel evolution equation for WIMP abundance considering gravitational particle production and analyzes its effects.

Findings

WIMP abundance is significantly affected by gravitational particle production.

The new model aligns with standard predictions under certain conditions.

Numerical and semi-analytical solutions validate the approach.

Abstract

A large set of independent astronomical observations have provided a strong evidence for nonbaryonic dark matter in the Universe. One of the most investigated candidates is an unknown long-lived Weakly Interacting Massive Particle (WIMP) which was in thermal equilibrium with the primeval plasma. Here we investigate the WIMP abundance based on the relativistic kinetic treatment for gravitationally induced particle production recently proposed in the literature (Lima \& Baranov, Phys. Rev. D {\bf 90}, 043515, 2014). The new evolution equation is deduced and solved both numerically and also through a semi-analytical approach. The predictions of the WIMP observables are discussed and compared with the ones obtained in the standard approach.