Study of χcJ decaying into K∗ (892) K ¯

Abstract

Using a data sample of 106 million ψ(3686) events collected with the BESIII detector operated at the BEPCII storage ring, we study for the first time the decays χcJ→ΦKS0K±π∓ and χcJ→ΦK+K-π0 in the E1 radiative transition ψ(3686)→γχcJ. The decays are dominated by the three-body decay χcJ→K∗(892)K¯. We measure branching fractions for this reaction via the neutral and charged K∗(892) and find them consistent with each other within the expectation of isospin symmetry. In the KK¯π invariant mass distribution, a structure near the K∗(892)K¯ mass threshold is observed, and the corresponding mass and width are measured to be 1412±4(stat)±8(sys)MeV/c2 and Γ=84±12(stat)±40(sys)MeV, respectively. The observed state favors an assignment to the h1(1380), considering its possible JPC and comparing its mass, width and decay mode to those reported in the Particle Data Group.