Chirally enhanced corrections to FCNC processes in the generic MSSM

TL;DR

This paper studies chirally enhanced supersymmetric QCD corrections to flavor-changing neutral current processes in the MSSM, showing how these corrections significantly impact parameter constraints and improve the accuracy of theoretical predictions.

Contribution

It introduces an efficient method to include higher-loop corrections into leading-order calculations for FCNC processes in the MSSM with flavor violation.

Findings

Corrections significantly alter parameter constraints from B->X_s gamma.

Stronger constraints on flavor-violating parameters for negative mu values.

Sub-percent squark mass differences lead to much tighter bounds from K mixing.

Abstract

Chirally enhanced supersymmetric QCD corrections to FCNC processes are investigated in the framework of the MSSM with generic sources of flavor violation. These corrections arise from flavor-changing self-energy diagrams and can be absorbed into a finite renormalization of the squark-quark-gluino vertex. In this way enhanced two-loop and even three-loop diagrams can be efficiently included into a leading-order (LO) calculation. Our corrections substantially change the values of the parameters delta^{d,LL}_{23}, delta^{d,LR}_{23}, delta^{d,RL}_{23}, and delta^{d,RR}_{23} extracted from Br[B->X_s gamma] if tan(beta) is large. We find stronger (weaker) constraints compared to the LO result for negative (positive) values of mu. The constraints on delta^{d,LR,RL}_{13} and delta^{d,LR,RL}_{23} from B_d mixing and B_s mixing change drastically if the third-generation squark masses differ from those of the first two generations. K mixing is more strongly affected by the chirally enhanced loop diagrams and even sub-percent deviations from degenerate down and strange squark masses lead to profoundly stronger constraints on delta^{d,LR,RL}_{12}.