B_s --> mu+mu- in Supersymmetric Grand Unified Theories

TL;DR

This paper explores how recent measurements of B_s --> mu+mu- can constrain supersymmetric grand unified theories, especially considering neutrino-induced flavor violations and their implications for related processes.

Contribution

It analyzes the impact of recent experimental data on supersymmetric GUT models, linking B_s decay measurements to tau decay predictions and flavor violation sources.

Findings

Lower bound on Br(tau --> mu gamma) from B_s measurement

Neutrino mixings induce squark flavor violation in GUT models

Predictions for Br(tau --> mu eta) based on Br(tau --> mu gamma)

Abstract

We investigate the recent CDF measurement of the Br(B_s --> mu+mu-) which shows excess over the Standard Model. We consider minimal supergravity motivated models (mSUGRA)/CMSSM and grand unified models, SU(5) and SO(10). In the grand unified models, the neutrino mixings provide an additional source of squark flavor violation through the quark-lepton unification. In the context of minimal SU(5) model, we find that the new CDF measurement has imposed a lower bound on the branching ratio of tau --> mu gamma for a large CP phase in the B_s-bar B_s mixing. Recall that there have been indication for a large CP phase in B_s mixing from B_s --> J/psi phi (Tevatron and LHCb) and dimuon asymmetry (D0). We also predict Br(tau --> mu eta) for the possible range of values of Br(tau --> mu gamma).