Observation of $\chi_{cJ}\to p \bar p K^0_S K^- \pi^+ + c.c.$

TL;DR

This paper reports the first observation of specific decay modes of the $oldsymbol{oldsymbol{ extit{ ext{chi}}}_{cJ}}$ particles into multi-particle final states, measuring their branching fractions with high statistical significance using BESIII data.

Contribution

First observation and measurement of branching fractions for $oldsymbol{oldsymbol{ extit{ ext{chi}}}_{cJ}}$ decays into $oldsymbol{p ar{p} K^0_S K^- ext{ extit{pi}}^+}$ and related channels, providing new insights into charmonium decay processes.

Findings

Observed $oldsymbol{ extit{ ext{chi}}}_{cJ}$ decays with >10$oldsymbol{ ext{ extsigma}}$ significance.

Measured branching fractions for $oldsymbol{ extit{ ext{chi}}}_{c0,1,2}}$ decays into specific multi-particle final states.

Detected $oldsymbol{ extit{ ext{chi}}}_{c1,2}$ decays into $oldsymbol{ar{p} ext{ extLambda}}(1520) K^0_S ext{ extpi}}^{+}$ with >5$oldsymbol{ ext{ extsigma}}$ significance.

Abstract

By analyzing $(27.12\pm0.14)\times10^8$ $\psi(3686)$ events collected with the BESIII detector operating at the BEPCII collider, the decays of $\chi_{cJ} \to p \bar{p} K^0_S K^- \pi^+ +c.c.(J=0, 1, 2)$ are observed for the first time with statistical significances greater than $10\sigma$. The branching fractions of these decays are determined to be $\mathcal{B}(\chi_{c0}\to p \bar p K^{0}_{S} K^- \pi^+ + c.c.)=(2.61\pm0.27\pm0.32)\times10^{-5},$ $\mathcal{B}(\chi_{c1}\to p \bar p K^{0}_{S} K^- \pi^+ + c.c.)=(4.16\pm0.24\pm0.46)\times10^{-5},$ and $\mathcal{B}(\chi_{c2}\to p \bar p K^{0}_{S} K^- \pi^+ + c.c.)=(5.63\pm0.28\pm0.46)\times10^{-5}$, respectively. The processes $\chi_{c1,2} \to \bar{p} \Lambda(1520) K^0_S \pi^{+} + c.c.$ are also observed, with statistical significances of 5.7$\sigma$ and 7.0$\sigma$, respectively. Evidence for $\chi_{c0} \to\bar{p} \Lambda(1520) K^0_S \pi^{+} + c.c.$ is found with statistical significances of 3.3$\sigma$ each. The corresponding branching fractions are determined to be $\mathcal{B}(\chi_{c0}\to \bar{p} \Lambda(1520) K^0_S \pi^{+} + c.c.) =(1.61^{+0.68}_{-0.64}\pm0.23)\times10^{-5}$, $\mathcal{B}(\chi_{c1}\to \bar{p} \Lambda(1520) K^0_S \pi^{+} + c.c.)=(4.06^{+0.80}_{-0.76}\pm0.52)\times10^{-5}$, and $\mathcal{B}(\chi_{c2}\to \bar{p} \Lambda(1520) K^0_S \pi^{+} + c.c.)=(4.09^{+0.87}_{-0.84}\pm0.42)\times10^{-5}$. Here, the first uncertainties are statistical and the second ones are systematic.