Measurement of branching fractions of $\hat{I}{›}_c^{+}\to p{K}_S^0{K}_S^0$ and $\hat{I}{›}_c^{+}\to p{K}_S^0\hat{I}\cdot$ at Belle

Abstract

We present a study of a singly Cabibbo-suppressed decay $\hat{I}{›}_c^{+}\to p{K}_S^0{K}_S^0$ and a Cabibbo-favored decay $\hat{I}{›}_c^{+}\to p{K}_S^0\hat{I}\cdot$ based on 980 $\mathrm{f}{\mathrm{b}}^{-1}$ of data collected by the Belle detector, operating at the KEKB energy-asymmetric $e^{+}{e}^{-}$ collider. We measure their branching fractions relative to $\hat{I}{›}_c^{+}\to p{K}_S^0$: $\mathcal{B}(\hat{I}{›}_c^{+}\to p{K}_S^0{K}_S^0)/\mathcal{B}(\hat{I}{›}_c^{+}\to p{K}_S^0)=(1.48\pm 0.08\pm 0.04)\times 10^{-2}$ and $\mathcal{B}(\hat{I}{›}_c^{+}\to p{K}_S^0\hat{I}\cdot )/\mathcal{B}(\hat{I}{›}_c^{+}\to p{K}_S^0)=(2.73\pm 0.06\pm 0.13)\times 10^{-1}$. Combining with the world average $\mathcal{B}(\hat{I}{›}_c^{+}\to p{K}_S^0)$, we have the absolute branching fractions: $\mathcal{B}(\hat{I}{›}_c^{+}\to p{K}_S^0{K}_S^0)=(2.35\pm 0.12\pm 0.07\pm 0.12)\times 10^{-4}$ and $\mathcal{B}(\hat{I}{›}_c^{+}\to p{K}_S^0\hat{I}\cdot )=(4.35\pm 0.10\pm 0.20\pm 0.22)\times 10^{-3}$. The first and second uncertainties are statistical and systematic, respectively, while the third ones arise from the uncertainty on $\mathcal{B}(\hat{I}{›}_c^{+}\to p{K}_S^0)$. The mode $\hat{I}{›}_c^{+}\to p{K}_S^0{K}_S^0$ is observed for the first time and has a statistical significance of $>10\ddot{I}ƒ$. The branching fraction of $\hat{I}{›}_c^{+}\to p{K}_S^0\hat{I}\cdot$ has been measured with a threefold improvement in precision over previous results and is found to be consistent with the world average.

8 pages, 4 figures, accepted by Phys. Rev. D