Higgs Inflation: Particle Factory

TL;DR

This paper investigates how Higgs inflation with nonminimal coupling leads to explosive gravitational particle production, potentially impacting dark matter relics and offering new insights into early universe particle dynamics.

Contribution

It reveals a new peak in gravitational particle production during Higgs inflation, significantly influenced by the nonminimal coupling parameter $\xi$, extending understanding beyond minimal coupling scenarios.

Findings

Peak particle production scales with $\xi$

Production dominates over minimal coupling cases

Applicable for $\xi$ as low as 10

Abstract

We study cosmological gravitational particle production (CGPP) in Higgs inflation, wherein the inflaton is a scalar field with quartic self-coupling $\lambda$ and a nonminimal coupling to gravity $\xi$, and which may, but need not be, the Higgs boson of the Standard Model (SM). We find an explosive particle production peaked on a characteristic comoving wavenumber $k\sim \xi^{2/3} a H$ with a peak occupation number that scales with $\xi$. This new peak in production can easily dominate over the conventional (minimally coupled inflation) CGPP even for modest values of $\xi$. The results apply for a wide range of $\xi$, e.g., as low as $\xi=10$, which can be realized for the Standard Model Higgs given suitable RG flow of the quartic coupling. We discuss implications for late time relics such as dark matter.