New physics in the weak interaction of (B)over-bar → D(*)τ(ν)over-bar

Recent experimental results on exclusive semitauonic B meson decays, (B) over bar -> D(*)tau(nu) over bar, showing sizable deviations from the standard model prediction, suggest a new physics in which the structure of the relevant weak charged interaction may differ from that of the standard model. We study the exclusive semitauonic B decays in a model-independent manner using the most general set of four-fermion interactions in order to clarify possible structures of the charged current in new physics. It turns out that correlations among observables including tau and D* polarizations and q(2) distributions are useful to distinguish possible new physics operators. Further, we investigate some interesting models to exhibit the advantage of our model-independent analysis. As a result, we find that two Higgs doublet models without tree-level flavor changing neutral currents and the minimal supersymmetric standard model with R-parity violation are unlikely to explain the present experimental data, while two Higgs doublet models with flavor changing neutral currents and a leptoquark model are consistent with the data. DOI: 10.1103/PhysRevD.87.034028