Flavorful new physics models in the light of the B decay anomalies

Abstract

Current experimental data on the flavor observables R_K and R_K^* shows evidence for a violation of lepton universality – an essential feature of the Standard Model of particle physics. Together with several deviations seen in other b -> sµ^+ µ^− observables as well as R_D and R_D^*, these results constitute the so-called B decay anomalies. In this thesis we investigate new physics models that provide potential solutions to these anomalies and put a special emphasis on their flavor structure. To this end, we consider an A4 x U(1)_FN based flavor symmetry, which addresses the SM flavor puzzle, and study patterns that it imposes on the couplings of leptoquark models. We find that flavorful leptoquarks provide good explanations of R_K^(*) , while constraints from rare kaon decays and charged lepton flavor violating processes are too strong to allow to accommodate the deviations in R_D^(*). As another consequence of the imposed flavor structure, flavorful leptoquarks are light enough to be produced at current and future hadron colliders. We compute estimates for the production cross sections of the S_3 , V_1 and V_3 leptoquarks in different flavor scenarios, focusing on single production, which is sensitive to the leptoquark coupling and its flavor structure. We find that future hadron colliders with higher center of mass energies are needed to cover the full parameter space and determine leptoquark mass bound for benchmark scenarios.