Baryogenesis through split Higgsogenesis

TL;DR

This paper proposes a new baryogenesis mechanism called split Higgsogenesis, where asymmetries in Higgs doublets are converted into baryon asymmetry via sphalerons, without requiring B-L violation, in a two-Higgs doublet model.

Contribution

It introduces a basis-independent framework for Higgs asymmetries and demonstrates a novel baryogenesis process through Higgs sector CP violation and out-of-equilibrium decays.

Findings

Higgs asymmetries can be converted into baryon asymmetry via sphalerons.

A basis-independent formulation of out-of-equilibrium conditions for Higgs interactions.

Simple scenarios show the viability of Higgsogenesis without B-L violation.

Abstract

We study the cosmological evolution of asymmetries in the two-Higgs doublet extension of the Standard Model, prior to the electroweak phase transition. If Higgs flavour-exchanging interactions are sufficiently slow, then a relative asymmetry among the Higgs doublets corresponds to an effectively conserved quantum number. Since the magnitude of the Higgs couplings depends on the choice of basis in the Higgs doublet space, we attempt to formulate basis-independent out-of-equilibrium conditions. We show that an initial asymmetry between the Higgs scalars, which could be generated by CP violation in the Higgs sector, will be transformed into a baryon asymmetry by the sphalerons, without the need of $B-L$ violation. This novel mechanism of baryogenesis through (split) Higgsogenesis is exemplified with simple scenarios based on the out-of-equilibrium decay of heavy singlet scalar fields into the Higgs doublets.