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

TL;DR

This paper explores how recent B meson decay measurements constrain squark flavor mixing in the MSSM, leading to new bounds on flavor violation parameters and predictions for rare top decays.

Contribution

It provides updated constraints on up-squark flavor mixing from B decay data and discusses implications for MSSM models and rare top decay rates.

Findings

Flavor mixing parameter (delta^u_23)_LR constrained to extless 0.1

Predicted BR(B_s --> mu+ mu-) extgreater 1 x 10^-9

Rare top decay BRs below current experimental sensitivities

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.