Anomalies in B mesons decays: a phenomenological approach

Abstract

The experimental measurements on flavour physics, in tension with Standard Model predictions, exhibit large sources of lepton flavour universality violation. We perform an analysis of the effects of the global fits on the Wilson coefficients assuming the Standard Model Effective Field Theory with semileptonic dimension six operators at 1 TeV, and by including a set of different scenarios in which the New Physics contributions to the Wilson coefficients are present in one, two or three of the Wilson coefficients at a time. We compare the results of the global fit with respect to two cases: the Standard Model and the more general case in which new physics modifies three independent Wilson coefficients. The last mentioned scenario is the favoured one for explaining the tension between Standard Model predictions and B-physics anomalies, but a specific more restricted scenario can provide similar goodness with a smaller set of free parameters. A discussion of the implications of our analysis in leptoquark models is included.