First Measurement of the $\hat{I}{›}_c^{+}\to p\hat{I}{\cdot }^{\prime }$ decay

Abstract

We present the first measurement of the branching fraction of the singly Cabibbo-suppressed (SCS) decay $\hat{I}{›}_c^{+}\to p\hat{I}{\cdot }^{\prime }$ with $\hat{I}{\cdot }^{\prime }\to \hat{I}\cdot \ddot{I}{€}^{+}\ddot{I}{€}^{-}$, using a data sample corresponding to an integrated luminosity of 981 $\mathrm{f}{\mathrm{b}}^{-1}$, collected by the Belle detector at the KEKB $e^{+}$$e^{-}$ asymmetric-energy collider. A significant $\hat{I}{›}_c^{+}$ signal is observed for the first time with a signal significance of 5.4$\ddot{I}ƒ$. The relative branching fraction with respect to the normalization mode $\hat{I}{›}_c^{+}\to p{K}^{-}\ddot{I}{€}^{+}$ is measured to be \begin{equation*} \frac{{\cal B}(Λ_c^+ \to p η')}{{\cal B}(Λ_c^+ \to p K^-π^+)} = (7.54 \pm 1.32 \pm 0.75) \times 10^{-3}, \end{equation*} where the uncertainties are statistical and systematic, respectively. Using the world-average value of $\mathcal{B}(\hat{I}{›}_c^{+}\to p{K}^{-}\ddot{I}{€}^{+})=(6.28\pm 0.32)\times 10^{-2}$, we obtain \begin{equation*} {\cal B}(Λ_c^+ \to p η') = (4.73 \pm 0.82 \pm 0.47 \pm 0.24)\times 10^{-4}, \end{equation*} where the uncertainties are statistical, systematic, and from $\mathcal{B}(\hat{I}{›}_c^{+}\to p{K}^{-}\ddot{I}{€}^{+})$, respectively.

14 pages, 2 figures, accepted for publication in JHEP