Constraining the MSSM sfermion mass matrices with light fermion masses

TL;DR

This paper investigates how loop corrections in the MSSM affect light fermion masses and mixing matrices, deriving strong bounds on flavor-changing parameters to ensure naturalness and implications for LHC top production.

Contribution

It provides the first detailed analysis of NLO supersymmetric loop corrections to fermion masses and mixing matrices, establishing new bounds on flavor-violating parameters in the MSSM.

Findings

Strong bounds on chirality-changing mass insertions delta^{f LR, RL}_{IJ}

Constraints on the unbounded element delta^{u RL}_{13}

Implications for single-top production at the LHC

Abstract

We study the finite supersymmetric loop corrections to fermion masses and mixing matrices in the generic MSSM. In this context the effects of non-decoupling chirally-enhanced self-energies are studied beyond leading order in perturbation theory. These NLO corrections are not only necessary for the renormalization of the CKM matrix to be unitary, they are also numerically important for the light fermion masses. Focusing on the tri-linear A-terms with generic flavor-structure we derive very strong bounds on the chirality-changing mass insertions delta^{f\,LR,RL}_{IJ} by applying 't Hooft's naturalness criterion. In particular, the NLO corrections to the up quark mass allow us to constrain the unbounded element delta^{u\,RL}_{13} if at the same time $\delta^{u\,LR}_{13}$ is unequal to zero. Our result is important for single-top production at the LHC.