CP violating transverse lepton polarizaion in $B\to D^{(\ast )}\ell \bar{\nu }$ including tensor interactions

Abstract

We give a model-independent analysis of CP violating lepton polarization in the exclusive semileptonic B decay of $B\to D^{(\ast )}\ell \bar{\nu }$ including dimension six four-fermion tensor interactions at the heavy quark limit. It is shown that the tensor interactions should not be neglected if the associated couplings are comparable to others. The effect of tensor interactions on the transverse lepton polarization appears more dramatically in $B\to D$ than in $B\to D^{\ast }$. In the leptoquark model, the average transverse lepton polarization is estimated to be $|\overline{P_D^{\perp }}|\simeq 0.26$ and $|\overline{P_{D^{\ast }}^{\perp }}|\simeq 0.076$ with commonly used model parameters.

Comments: 17 pages, figures and references are added, to appear in Phys. Lett. B