Anomalous enhancement observed in B → D(*)τ(ν)over-barτ decays

The BABAR measurements of the ratios R(D-(*)) = B(B -> D-(*)tau(nu) over bar (tau))/B(B -> D-(*)mu(nu) over bar (mu)) deviate from the standard model expectation, while new results on the purely leptonic B -> tau(nu) over bar (tau) mode show a better consistency with the standard model, within the uncertainties. In a new physics scenario, one possibility to accommodate these two experimental facts consists in considering an additional tensor operator in the effective weak Hamiltonian. We study the effects of such an operator in a set of observables, in semileptonic B -> D-(*) modes as well as in semileptonic B and B-s decays to excited positive-parity charmed mesons. DOI: 10.1103/PhysRevD.87.074010