Dispersion relations for $B^{-}\to {\ell }^{-}{\bar{\nu }}_{\ell }{\ell }^{\prime -}{\ell }^{\prime +}$ form factors

Stephan Kürten, Marvin Zanke, Bastian Kubis +1

Using dispersive methods, we study the $B\to {\gamma }^{\ast }$ form factors underlying the decay $B^{-}\to {\ell }^{-}{\bar{\nu }}_{\ell }{\ell }^{\prime -}{\ell }^{\prime +}$. We discuss the ambiguity that arises…