Measurement of the Branching Fraction of the Decay ${\mathbf{B}}^{+}\to {\mathbf{\pi }}^{+}{\mathbf{\pi }}^{-}{\mathbf{\ell }}^{+}{\mathbf{\nu }}_{\mathbf{\ell }}$ in Fully Reconstructed Events at Belle

The Belle Collaboration, C. Beleño, A. Frey +160

We present an analysis of the exclusive $B^{+}\to {\pi }^{+}{\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ decay, where $\ell$ represents an electron or a muon, with the assumption of charge-conjugation symmetr…