Lepton Flavor Violation in B Decays?

TL;DR

This paper discusses the potential for lepton flavor violation in B decays due to new physics suggested by deviations in R_K measurements, proposing a simple model consistent with current experimental limits.

Contribution

The paper introduces a simple model that links the R_K anomaly to lepton flavor violation in B decays, aligning with recent experimental bounds.

Findings

The model predicts lepton flavor violation rates just below current experimental limits.

The ratio B(B_s -> mu+ mu-)/B(B_s -> mu+ mu-)_{SM} can match the observed R_K value.

Lepton flavor violating decays like B -> K mu e are promising search channels.

Abstract

The LHCb Collaboration's measurement of R_K = B(B+ -> K+ mu+ mu-)/B(B+ -> K+ e+e-) lies 2.6 sigma below the Standard Model prediction. Several groups suggest this deficit to result from new lepton non-universal interactions of muons. But non-universal leptonic interactions imply lepton flavor violation in B decays at rates much larger than are expected in the Standard Model. A simple model shows that these rates could lie just below current limits. An interesting consequence of our model, that B(B_s -> mu+ mu-)_{exp}/B(B_s -> mu+ mu-)_{SM} = R_K = 0.75, is compatible with recent measurements of these rates. We stress the importance of searches for lepton flavor violations, especially for B -> K mu e, K mu tau and B_s -> mu e, mu tau.