Unified explanation of flavor anomalies, radiative neutrino masses, and ANITA anomalous events in a vector leptoquark model

Abstract

Driven by the recent experimental hints of lepton-flavor-universality violation in the bottom-quark sector, we consider a simple extension of the Standard Model (SM) with an additional vector leptoquark VLQ(3,1,2/3) and a scalar diquark SDQ(6,1,4/3) under the SM gauge group SU(3)c×SU(2)L×U(1)Y, in order to simultaneously explain the b→s+- (with =e, μ) and b→cl-ν¯l (with l=e, μ, τ) flavor anomalies, as well as to generate small neutrino masses through a two-loop radiative mechanism. We perform a global fit to all the relevant and up-to-date b→s+- and b→cl-ν¯l data under the assumption that the leptoquark couples predominantly to second and third-generation SM fermions. We then look over the implications of the allowed parameter space on lepton-flavor-violating B and τ decay modes, such as Bs→li+lj-, B→K(∗)li+lj-, Bs→φli+lj-, (nS)→μτ, and τ→μγ, τ→μφ(η(′)), respectively. Minimally extending this model by adding a fermion singlet χ(1,1,0) also explains the ANITA anomalous upgoing events. Furthermore, we provide complementary constraints on leptoquark and diquark couplings from high-energy collider and other low-energy experiments to test this model.