Constraints on lepton flavor violation in the MSSM from the muon anomalous magnetic moment measurement

Abstract

We establish a correspondence between those Feynman diagrams in the MSSM which give supersymmetric contributions to the muon anomalous magnetic moment and those which contribute to the flavor violating processes $μ--> eγ$ and $τ--> μγ$. Using current experimental limits on the branching ratios of these decay modes, combined with the assumption of a supersymmetric contribution to the muon anomalous magnetic moment, we establish bounds on the size of the lepton flavor violating soft masses in the MSSM largely independent of assumptions about other supersymmetric parameters. If the deviation measured at Brookhaven National Laboratory is from supersymmetry, we find the bounds ${m^2}_{e μ}/ {\bar{m}^2} \lsim 2 \times 10^{-4}$ and ${m^2}_{τμ}/ {\bar{m}^2} \lsim 1 \times 10^{-1}$, where ${\bar{m}}^2$ is the mass of the heaviest particle in any loop that contributes at this level to the anomalous magnetic moment of the muon. This provides a significant constraint on the non-flavor-blind mediation of supersymmetry breaking that often occurs at a suppressed level in many models, including gaugino mediation.