Observation of Λ+c→nK0Sπ+

We report the first direct measurement of decays of the A+c baryon involving the neutron. The analysis is performed using 567 pb?1 of e+e? collision data collected at √s = 4.599 GeV withthe BESIII detector at the BEPCII collider. We observe the decay A+c→nK0S π+ and measure the absolute branching fraction to be B(Α+c→nK0S π+) = (1.82 ± 0.23(stat) ± 0.11(syst))%. Acomparison to B(Α+c → p( Kπ )0) provides an important test of isospin symmetry and final stateinteractions.