$τ$ polarization asymmetries in $B^+ \to τ^+ν_τγ$ and $B^+_c \to τ^+ν_τγ$

Abstract

We study the lepton polarization asymmetries in the radiative leptonic B decays of $B^+\to l^+ν_{l}γ$ and $B^+_{c}\to l^+ν_{l}γ$. We concentrate on the transverse component of the $τ$ lepton asymmetries in the tau decay modes due to CP violation in theories beyond the standard model to search T violating effect.