MSSM Electroweak Baryogenesis and LHC Data

TL;DR

This paper explores how the MSSM can accommodate electroweak baryogenesis while remaining consistent with LHC data, highlighting the role of a light neutralino and specific stop decay channels for future collider tests.

Contribution

It demonstrates that the tension between electroweak baryogenesis requirements and Higgs data can be alleviated with a light neutralino, proposing new collider signatures.

Findings

Light neutralino relaxes tension with Higgs data

Stop decays involve three or four body channels

Scenario testable at high luminosity LHC

Abstract

Electroweak baryogenesis is an attractive scenario for the generation of the baryon asymmetry of the universe as its realization depends on the presence at the weak scale of new particles which may be searched for at high energy colliders. In the MSSM it may only be realized in the presence of light stops, and with moderate or small mixing between the left- and right-handed components. Consistency with the observed Higgs mass around 125 GeV demands the heavier stop mass to be much larger than the weak scale. Moreover the lighter stop leads to an increase of the gluon-gluon fusion Higgs production cross section which seems to be in contradiction with indications from current LHC data. We show that this tension may be considerably relaxed in the presence of a light neutralino with a mass lower than about 60 GeV, satisfying all present experimental constraints. In such a case the Higgs may have a significant invisible decay width and the stop decays through a three or four body decay channel, including a bottom quark and the lightest neutralino in the final state. All these properties make this scenario testable at a high luminosity LHC.