First measurement of the $$ {\Lambda}_c^{+} $$ ? p?? decay

We present the first measurement of branching fraction singly Cabibbo-suppressed (SCS) decay $\Lambda_c^+ \to p \eta'$ with $\eta' \eta\pi^+\pi^-$, using a data sample corresponding to an integrated luminosity 981 $\rm fb^{-1}$, collected by Belle detector at KEKB $e^{+}$$e^{-}$ asymmetric-energy collider. A significant $\Lambda_c^+$ signal is observed for time significance 5.4$\sigma$. The relative respect normalization mode pK^-\pi^+$ measured be \begin{equation*} \frac{{\cal B}(\Lambda_c^+ \eta')}{{\cal K^-\pi^+)} = (7.54 \pm 1.32 0.75) \times 10^{-3}, \end{equation*} where uncertainties are statistical and systematic, respectively. Using world-average value ${\cal K^-\pi^+) (6.28\pm0.32)\times10^{-2}$, we obtain {\cal \eta') (4.73 0.82 0.47 0.24)\times 10^{-4}, statistical, from pK^-\pi^+)$,