RK* Analysis and Lepton Flavour Universality

The Standard Model predicts that charged leptons such as electrons and muons should have identical electroweak interaction strengths, which is known as lepton flavour universality. However, in some specific beauty quark decays, recent experimental results indicate that the ratio between branching fractions of electron and muon channels of the same decay may be deviant from unity, suggesting violations of the universality. In this work, we study the decay Bd0 → K∗0l+l−, where l− represents an electron or a muon, in preparation for the measurement of the ratio R(K*), which is the ratio of the branching fraction of the muon decay channel to that of the electron decay channel with normalization considering resonant decays that also produce the same particle products.