A model-independent analysis of $b \to s \mu^+ \mu^-$ transitions with GAMBIT's FlavBit

TL;DR

This paper performs a comprehensive, model-independent global fit of Wilson coefficients in $b o s \, \mu^+ \mu^-$ transitions using GAMBIT's FlavBit, revealing a significant deviation from the Standard Model with a 6.6 sigma significance.

Contribution

It introduces an extended analysis that accounts for correlated theoretical uncertainties in Wilson coefficients, improving upon previous studies.

Findings

Best fit deviates from SM by 6.6 sigma

Largest deviation linked to muon vector coupling

Analysis includes correlated theoretical uncertainties

Abstract

The search for flavour-changing neutral current effects in $B$-meson decays is a powerful probe of physics beyond the Standard Model. Deviations from SM behaviour are often quantified by extracting the preferred values of the Wilson coefficients of an operator product expansion. We use the FlavBit module of the GAMBIT package to perform a simultaneous global fit of the Wilson coefficients $C_7$, $C_9$, and $C_{10}$ using a combination of all current data on $b \to s \mu^+ \mu^-$ transitions. We further extend previous analyses by accounting for the correlated theoretical uncertainties at each point in the Wilson coefficient parameter space, rather than deriving the uncertainties from a Standard Model calculation. We find that the best fit deviates from the SM value with a significance of 6.6$\sigma$. The largest deviation is associated with a vector coupling of muons to $b$ and $s$ quarks.