The Baryogenesis Window in the MSSM

TL;DR

This paper evaluates the parameter space in the MSSM where electroweak baryogenesis can occur, identifying specific mass ranges for the stop and Higgs bosons that are testable at the LHC.

Contribution

It provides a detailed analysis of the stop and Higgs mass window in the MSSM consistent with electroweak baryogenesis, including two-loop effects and metastability considerations.

Findings

Allowed (m_stop, m_H) window identified

Upper bounds: m_H ≲ 127 GeV, m_stop ≲ 120 GeV

Scenario testable at the LHC

Abstract

Electroweak baryogenesis provides an attractive explanation of the origin of the matter-antimatter asymmetry that relies on physics at the weak scale and thus it is testable at present and near future high-energy physics experiments. Although this scenario may not be realized within the Standard Model, it can be accommodated within the MSSM provided there are new CP-violating phases and the lightest stop mass is smaller than the top-quark mass. In this work we provide an evaluation of the values of the stop (m_{\tilde t}) and Higgs (m_H) masses consistent with the requirements of electroweak baryogenesis based on an analysis that makes use of the renormalization group improved Higgs and stop potentials, and including the dominant two-loop effects at high temperature. We find an allowed window in the (m_{\tilde t},m_H)-plane, consistent with all present experimental data, where there is a strongly first-order electroweak phase transition and where the electroweak vacuum is metastable but sufficiently long-lived. In particular we obtain absolute upper bounds on the Higgs and stop masses, m_H\lesssim 127 GeV and m_{\tilde t}\lesssim 120 GeV, implying that this scenario will be probed at the LHC.