Baryon Asymmetry of the Universe in the NuMSM

TL;DR

This paper analyzes how the NuMSM model can generate the universe's baryon asymmetry, constraining its parameters based on neutrino data and baryogenesis requirements, with implications for experimental searches.

Contribution

It provides a detailed parameter space analysis of the NuMSM for successful baryogenesis, including constraints on fermion mass splitting and couplings.

Findings

Constraints on singlet fermion mass splitting

Limits on fermion-lepton coupling strength

Guidance for experimental searches in meson decays and beam-dump experiments

Abstract

We perform a detailed analysis of baryon asymmetry generation in the NuMSM (an extension of the Standard Model by three singlet Majorana fermions with masses below the Fermi scale). Fixing a number of parameters of the NuMSM by the neutrino oscillation data, we determine the remaining domain of the parameter space from the requirement of successful baryogenesis. We derive, in particular, the constraints on the mass splitting of a pair of singlet fermions, and on the strength of their coupling to ordinary leptons, essential for searches of these particles in rare decays of mesons and in beam-dump experiments with intensive proton beams.