The Light Stop Scenario from Gauge Mediation

TL;DR

This paper presents a top-down model embedding the light stop scenario within the MSSM, explaining baryogenesis and predicting a Higgs mass near the experimental lower bound through a combination of gauge and gravity mediation.

Contribution

It introduces a natural high-energy origin for the light stop spectrum using mixed gauge and gravity mediation, aligning with electroweak baryogenesis and Higgs mass constraints.

Findings

Predicts a Higgs mass around the lower experimental bound.

Achieves a light stop scenario compatible with baryogenesis.

Provides a natural RG-driven spectrum from high-energy supersymmetry breaking.

Abstract

In this paper we embed the light stop scenario, a MSSM framework which explains the baryon asymmetry of the universe through a strong first order electroweak phase transition, in a top-down approach. The required low energy spectrum consists in the light SM-like Higgs, the right-handed stop, the gauginos and the Higgsinos while the remaining scalars are heavy. This spectrum is naturally driven by renormalization group evolution starting from a heavy scalar spectrum at high energies. The latter is obtained through a supersymmetry-breaking mix of gauge mediation, which provides the scalars masses by new gauge interactions, and gravity mediation, which generates gaugino and Higgsino masses. This supersymmetry breaking also explains the \mu\ and B_\mu\ parameters necessary for electroweak breaking and predicts small tri-linear mixing terms A_t in agreement with electroweak baryogenesis requirements. The minimal embedding predicts a Higgs mass around its experimental lower bound and by a small extension higher masses m_H\lesssim 127 GeV can be accommodated.