Optimal-observable analysis of possible new physics in B → D(*)τντ

We study all possible observables in B -> D-(*)tau nu(tau) with new physics (NP), including new vector, scalar and tensor interactions, and investigate the prospects of extracting NP Wilson coefficients with optimal observables. The analysis shows that, overall, the full q(2) integrated observables in B -> D tau nu(tau) are more sensitive towards the scalar current, whereas the bin-by-bin analysis of q(2) distribution of the differential branching fraction points to regions of q(2) sensitive to tensor interactions. Interestingly, the observables in B -> D*tau nu(tau) are more sensitive to tensor interactions, and bin-by-bin analysis of this mode shows the distinct regions of q(2) sensitive to vector or scalar interactions. In addition to that, the tau polarization asymmetry is found to be more sensitive to NP compared to the other observables, in both decay modes.