Flavour anomalies

Abstract

The LHC observed deviations from the Standard Model (SM) in the flavor sector: LHCb found a 4.3σ discrepancy compared to the SM in b → sμμ transitions and CMS reported a non-zero measurement of h → μτ with a significance of 2.4σ. Here we discuss how these deviations from the SM can be explained, focusing on two models with gauged Lμ – Lτ symmetry. The first model contains two scalar doublets and vector-like quarks while the second one employs three scalar doublets but does not require vectorlike fermions. In both models, interesting correlations between b → sμμ transitions, h → μτ, and τ → 3μ arise. We have also studied lepton flavor (universality) violation in rare kaon decays and the Bardeen Buras Gerard approach to describe the K± → π±l+l− form factor.