Hint of Lepton Flavour Non-Universality in $B$ Meson Decays

• Main Authors: Ghosh, Diptimoy, Nardecchia, Marco, Renner, S. A
• Format: Journal Article
• Language: English
• Published: 18-08-2014
• Subjects: Physics - High Energy Physics - Experiment; Physics - High Energy Physics - Phenomenology
• DOI: 10.48550/arxiv.1408.4097

The LHCb collaboration has recently presented their result on R_K = BR(B+ ->
K+ mu+ mu-)/ BR(B+ -> K+ e+ e-) for the dilepton invariant mass bin m_{ll}^2 =
1-6 GeV^2 (l = mu, e). The measurement shows an intriguing 2.6 sigma deviation
from the Standard Model (SM) prediction. In view of this, we study model
independent New Physics (NP) explanations of R_K consistent with other
measurements involving b -> s l l transition, relaxing the assumption of lepton
universality. We perform a Bayesian statistical fit to the NP Wilson
Coefficients and compare the Bayes Factors of the different hypotheses in order
to quantify their goodness-of-fit. We show that the data slightly favours NP in
the muon sector over NP in the electron sector.