Probing BSM Physics in B→D^*lν Using Monte Carlo Simulation

Several experimental measurements of b-decays have suggested the presence of physics beyond the Standard Model (BSM). One set of such measurements are the decay modes B→D^*lν with l=e, μ, and τ. A recent analysis of 2019 Belle data found ΔA_FB = A_FB(B→D^*μν) - A_FB(B→D^*eν) to be 4.1σ away from the SM prediction. Improved simulation and analysis tools are needed in order to more effectively probe these new physics (NP) possibilities. We have developed a Monte-Carlo event generator tool based on the EVTGEN framework to simulate NP signatures in B→D^*lν, which arise due to the interference between the SM and NP amplitudes. We have also simulated several example NP scenarios which are able to explain the ΔA_FB anomaly, while remaining consistent with experimental constraints. We also show that Δ-type observables allow for definite signals of NP by removing most QCD uncertainties from the form factors, and introduce several correlated observables that allow for more sensitivity to NP.