Evidence for $B^0\to p{\bar{\mathrm{\Sigma }}}^0{\pi }^{-}$ at Belle

We search for the $B^0\to p{\bar{\mathrm{\Sigma }}}^0{\pi }^{-}$ decay with ${\bar{\mathrm{\Sigma }}}^0\to \bar{\mathrm{\Lambda }}\gamma$, where the $\gamma$ is not measured, using a data sample corresponding to an integrated luminosity of 711 $\mathrm{f}{\mathrm{b}}^{-1}$ which contains 772 $\times$ ${10}^6$ $B\bar{B}$ pairs, collected around the $\mathrm{{\rm Y}}$(4S) resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. We measure for the first time the $B^0\to p{\bar{\mathrm{\Sigma }}}^0{\pi }^{-}$ branching fraction to be $\mathcal{B}(B^0\to p{\bar{\mathrm{\Sigma }}}^0{\pi }^{-})=(1.17_{-0.40}^{+0.43}(\text{stat})\pm 0.07(\text{syst}))\times {10}^{-6}$ with a significance of $3.0\sigma$. We simultaneously measure the branching fraction for the related channel $B^0\to p\bar{\mathrm{\Lambda }}{\pi }^{-}$ with much improved precision.