Soft-Photon Corrections to $\bar{B}\to D{\tau }^{-}{\bar{\nu }}_{\tau }$ Relative to $\bar{B}\to D{\mu }^{-}{\bar{\nu }}_{\mu }$

Stefan de Boer, Teppei Kitahara, Ivan Nisandzic

We evaluate long-distance electromagnetic (QED) contributions to $\bar{B}{}^0\to D^{+}{\tau }^{-}{\bar{\nu }}_{\tau }$ and $B^{-}\to D^0{\tau }^{-}{\bar{\nu }}_{\tau }$ relative to $\bar{B}{}^0\to D^{+}{\mu }^{-}{\bar{\nu }}_{\mu }$…