A Reconsideration of the b -> s gamma Decay in the Minimal Flavor Violating MSSM

TL;DR

This paper investigates the b -> s gamma decay within the Minimal Flavor Violating MSSM, highlighting the significant role of gluino contributions, especially at large tan(beta), and revealing complex cancellations among different SUSY contributions.

Contribution

It provides a detailed analysis of gluino contributions in the MFV MSSM, which are often neglected, and demonstrates their potential dominance and the absence of strict lower bounds on SUSY masses due to cancellations.

Findings

Gluino contributions can dominate at large tan(beta).

No absolute lower bounds on SUSY masses due to cancellations.

Gluino, chargino, and Higgs contributions can cancel each other.

Abstract

We present a MSSM study of the b -> s gamma decay in a Minimal Flavor Violating (MFV) framework, where the form of the soft SUSY breaking terms is determined by the Standard Model Yukawa couplings. In particular, we address the role of gluino contributions, which are set to zero in most studies of the MFV MSSM. Gluino contributions can play an important role in the MFV MSSM whenever mu * tan(beta) is large. In fact, similarly to chargino contributions, gluino contributions are tan(beta) enhanced and can easily dominate charged Higgs contributions for large values of tan(beta). Even though each of the separate contributions to b -> s gamma can be sizeable by itself, surprisingly no absolute lower bound can be placed on any of the relevant SUSY masses, since patterns of partial cancellations among the three competing contributions (Higgs, chargino and gluino) can occur throughout the MSSM parameter space.