Preheating the Universe from the Standard Model Higgs

TL;DR

This paper explores the complex preheating process after inflation driven by the Standard Model Higgs, highlighting the interplay of perturbative and non-perturbative effects, gauge boson production, and fermion decay, with implications for early universe thermalization.

Contribution

It provides a detailed analysis of the preheating dynamics involving the SM Higgs, including gauge boson production, fermion decay, and backreaction effects, which were not fully understood before.

Findings

Gauge bosons are produced non-perturbatively from the Higgs condensate.

Fermions rapidly decay into gauge bosons, preventing parametric resonance initially.

Backreaction effects become significant, influencing the energy distribution and evolution.

Abstract

We discuss Preheating after an inflationary stage driven by the Standard Model (SM) Higgs field non-minimally coupled to gravity. We find that Preheating is driven by a complex process in which perturbative and non-perturbative effects occur simultaneously. The Higgs field, initially an oscillating coherent condensate, produces non-perturbatively W and Z gauge fields. These decay very rapidly into fermions, thus preventing gauge bosons to accumulate and, consequently, blocking the usual parametric resonance. The energy transferred into the fermionic species is, nevertheless, not enough to reheat the Universe, and resonant effects are eventually developed. Soon after resonance becomes effective, also backreaction from the gauge bosons into the Higgs condensate becomes relevant. We have determined the time evolution of the energy distribution among the remnant Higgs condensate and the non-thermal distribution of the SM fermions and gauge fields, until the moment in which backreaction becomes important. Beyond backreaction our approximations break down and numerical simulations and theoretical considerations beyond this work are required, in order to study the evolution of the system until thermalization.