Analyzing new physics in the decays (B)over-bar0 → D(*)τ-(ν)over-barτ with form factors obtained from the covariant quark model

We study possible new physics (NP) effects in the exclusive decays (B) over bar (0) -> D-(*())tau(-)(nu) over bar (tau). We extend the Standard Model by taking into account right-handed vector (axial), left-and right-handed (pseudo) scalar, and tensor current contributions. The (B) over bar (0) -> D-(*()) transition form factors are calculated in the full kinematic q(2) range by employing a covariant quark model developed by us. We provide constraints on NP operators based on measurements of the ratios of branching fractions R(D-(*())) = B((B) over bar (0) -> D-(*())tau(-)(nu) over bar (tau)/B((B) over bar (0) -> D-(*()) mu(-)(nu) over bar (mu)) and consider the effects of these operators on physical observables in different NP scenarios. We also derive the fourfold angular distribution for the cascade decay (B) over bar (0) -> D*(+)(-> D-0 pi(+))tau(-)(nu) over bar (tau) which allows one to analyze the polarization of the D* meson in the presence of NP effects. We discuss several strategies to distinguish between various NP contributions.