Model for the singlet-triplet leptoquarks

Abstract

The deviations of B-meson decays measured in RD(∗)τℓ and RK(∗)μe can be explained by the presence of two scalar leptoquarks, a singlet S1 and a triplet S3, mostly coupled to the third generation. We consider a theory of resonances, as an effective description of a strongly interacting theory, that generates the leptoquarks and the Higgs as Nambu-Goldstone bosons, with the rest of the resonances at a scale of order 10-30 TeV. We assume anarchic partial compositeness for the flavor of the SM fermions. Under this hypothesis, we study whether it is possible to reproduce the deviations in the B decays without being in conflict with flavor and electroweak bounds. We find a tension between RD(∗)τℓ and some flavor observables, dominated by flavor violating τ decays and ΔmBs, that require a tuning of order 10%-25%. We also compute the potential of the scalars showing that leptoquarks with masses O(2-3) TeV can be naturally expected in the model. We discuss briefly the phenomenology of the other resonances.