$\tau$ polarization asymmetries in $B^{+}\to {\tau }^{+}{\nu }_{\tau }\gamma$ and $B_c^{+}\to {\tau }^{+}{\nu }_{\tau }\gamma$

C. Q. Geng, C. C. Lih, T. H. Wu

We study the lepton polarization asymmetries in the radiative leptonic B decays of $B^{+}\to l^{+}{\nu }_l\gamma$ and $B_c^{+}\to l^{+}{\nu }_l\gamma$. We concentrate on the transverse component of the…