Observation of $\hat{I}{›}_c^{+}\to n{K}_S^0\ddot{I}{€}^{+}$

Abstract

We report the first direct measurement of decays of the $\hat{I}{›}_c^{+}$ baryon involving the neutron. The analysis is performed using 567 pb${}^{-1}$ of $e^{+}{e}^{-}$ collision data collected at $\sqrt{s}=4.599$ GeV with the BESIII detector at the BEPCII collider. We observe the decay $\hat{I}{›}_c^{+}\to n{K}_S^0\ddot{I}{€}^{+}$ and measure the absolute branching fraction to be $\mathcal{B}(\hat{I}{›}_c^{+}\to n{K}_S^0\ddot{I}{€}^{+})=(1.82\pm 0.23(\mathrm{stat})\pm 0.11(\mathrm{syst}))\%$. A comparison to $\mathcal{B}(\hat{I}{›}_c^{+}\to p(\bar{K}\ddot{I}€{)}^0)$ provides an important test of isospin symmetry and final state interactions.

6 pages, 2 figures