Postinflationary Higgs relaxation and the origin of matter-antimatter asymmetry

TL;DR

This paper proposes a mechanism where the Higgs field's relaxation after inflation generates a lepton asymmetry, which is then converted into the observed matter-antimatter asymmetry, all within the Standard Model framework.

Contribution

It introduces a novel leptogenesis scenario driven by Higgs relaxation during postinflation, explaining matter-antimatter asymmetry without new physics beyond the Standard Model.

Findings

Higgs relaxation can produce sufficient lepton asymmetry

The mechanism is compatible with Standard Model validity up to inflation scale

Electroweak sphalerons convert lepton asymmetry into baryon asymmetry

Abstract

The recent measurement of the Higgs boson mass implies a relatively slow rise of the Standard Model Higgs potential at large scales, and a possible second minimum at even larger scales. Consequently, the Higgs field may develop a large vacuum expectation value during inflation. The relaxation of the Higgs field from its large postinflationary value to the minimum of the effective potential represents an important stage in the evolution of the universe. During this epoch, the time-dependent Higgs condensate can create an effective chemical potential for the lepton number, leading to a generation of the lepton asymmetry in the presence of some large right-handed Majorana neutrino masses. The electroweak sphalerons redistribute this asymmetry between leptons and baryons. This Higgs relaxation leptogenesis can explain the observed matter-antimatter asymmetry of the universe even if the Standard Model is valid up to the scale of inflation, and any new physics is suppressed by that high scale.