Global Bayesian Analysis of new physics in $b\to s\mu \mu$ transitions after Moriond-2019

Abstract

The recent measurement of $R_K$ at LHCb continues to support the hint of violation of lepton flavor universality. We perform a global fit for new physics in semileptonic $b\to s$ transitions using all the relevant data with a Bayesian analysis technique. We include new measurements of $R_K$ at LHCb and new determinations of $R_{K^{\ast }}$ and $R_{K^{\ast +}}$ at Belle. We perform the scan for various NP scenarios and infer the 68\% and 95.4\% credibility regions of the marginalized posterior probability density for all scenarios. We also compare the models in pairs by calculating the Bayes factor given a common data set. A few well-known BSM models are analyzed that can provide a high energy framework for the EFT analysis. These include the exchange of a heavy $Z^{{}^{\prime }}$ boson in models with heavy vector-like fermions and a scalar field, and a model with scalar leptoquarks. We provide predictions for the BSM couplings and expected mass values.

Comments: 4 pages, 6 figures, Proceedings for FPCP 2019