Electroweak baryogenesis in the MSSM with vector-like quarks

TL;DR

This paper explores how adding vector-like quarks to the MSSM allows for a strongly first-order electroweak phase transition without requiring a light scalar top quark, expanding the viable parameter space for baryogenesis.

Contribution

It demonstrates that vector-like quarks enable a strong first-order EWPT in the MSSM without the need for light scalar top quarks, under specific Higgs mass conditions.

Findings

Strong first-order EWPT possible with vector-like quarks

EWPT strength depends on Higgs mass and quark mixing

No need for light scalar top quark in extended MSSM

Abstract

In the minimal supersymmetric standard model (MSSM), a strongly first-order electroweak phase transition (EWPT) is only possible in a confined parameter region where one of the scalar top quarks is lighter than the top quark and the other one is as heavy as the SUSY breaking scale. If the MSSM is enlarged to accommodate vector-like quarks and their superpartners, we find that the strongly first-order EWPT is possible without requiring light scalar top quark at the one-loop level, in the limit where the lightest scalar Higgs boson of the MSSM behaves like the Higgs boson of the standard model and the other Higgs bosons are all as heavy as the SUSY breaking scale. The strength of the first-order EWPT is found to be dependent on the mass of the lightest neutral Higgs boson and the mixing effects of the vector-like scalar quarks.