Squark Flavor Implications from B --> K(*) l+ l-

Abstract

Recent experimental and theoretical progress regarding B --> K(*) l+ l- decays led to improved bounds on the Wilson coefficients C_9 and C_10 of four-fermion operators of the |Delta B|=|Delta S|=1 effective Hamiltonian. We analyze the resulting implications on squark flavor violation in the MSSM and obtain new constraints on flavor-changing left-right mixing in the up-squark-sector. We find the dimensionless flavor mixing parameter (delta^u_23)_LR, depending on the flavor-diagonal MSSM masses and couplings, to be as low as \lesssim 0.1. This has implications for models based on radiative flavor violation and leads to BR(B_s --> mu+ mu-) \gtrsim 1 x 10^-9. Rare top decays t --> c gamma, t --> c g, t --> c Z have branching ratios predicted to be below \lesssim few times 10^-8, 10^-6 and 10^-7, respectively.