Large Density Perturbations from Reheating to Standard Model particles due to the Dynamics of the Higgs Boson during Inflation

TL;DR

This paper investigates how the Higgs boson during inflation causes large density perturbations through its effects on SM particles, constraining reheating scenarios based on CMB observations.

Contribution

It provides new constraints on reheating temperatures and rules out certain preheating mechanisms due to large density fluctuations caused by the Higgs field during inflation.

Findings

Strong constraints on reheating temperature for heavy SM particles.

Resonant preheating produces temperature fluctuations exceeding CMB observations.

Preheating via Higgsed gauge bosons cannot be the main reheating mechanism.

Abstract

Cosmic Microwave Background (CMB) observations are used to constrain reheating to Standard Model (SM) particles after a period of inflation. As a light spectator field, the SM Higgs boson acquires large field values from its quantum fluctuations during inflation, gives masses to SM particles that vary from one Hubble patch to another, and thereby produces large density fluctuations. We consider both perturbative and resonant decay of the inflaton to SM particles. For the case of perturbative decay from coherent oscillations of the inflaton after high scale inflation, we find strong constraints on the reheat temperature for the inflaton decay into heavy SM particles. For the case of resonant particle production (preheating) to (Higgsed) SM gauge bosons, we find temperature fluctuations larger than observed in the CMB for a range of gauge coupling that includes those found in the SM and conclude that such preheating cannot be the main source of reheating the Universe after inflation.