Observation of $\psi(3686)\to\Xi(1530)^{0}\bar{\Xi}(1530)^{0}$ and $\Xi(1530)^{0}\bar{\Xi}^0$

TL;DR

This paper reports the first observation of specific decay modes of the $oldsymbol{\psi(3686)}$ particle into baryon-antibaryon pairs, measuring their branching fractions and angular distribution parameters with high statistical significance.

Contribution

It provides the first experimental measurement of these decay modes and their angular distribution, confirming theoretical predictions within uncertainties.

Findings

First observation of $oldsymbol{\psi(3686) o\Xi(1530)^{0}ar{\Xi}(1530)^{0}}$ and $oldsymbol{\psi(3686) o\\Xi(1530)^{0}ar{\\Xi}^0}$ decays.

Measured branching fractions: $(6.77 ext{e-5}, 0.53 ext{e-5})$ with uncertainties.

Angular distribution parameter $oldsymbol{\alpha=0.32 ext{ with uncertainties}}$ in agreement with theory.

Abstract

Using $(448.1\pm2.9)\times 10^{6}$ $\psi(3686)$ events collected with the BESIII detector and a single-baryon tagging technique, we present the first observation of the decays $\psi(3686)\to\Xi(1530)^{0}\bar{\Xi}(1530)^{0}$ and $\Xi(1530)^{0}\bar{\Xi}^0$. The branching fractions are measured to be ${\cal{B}}(\psi(3686)\to\Xi(1530)^{0}\bar{\Xi}(1530)^{0}) = (6.77\pm0.14\pm0.39)\times10^{-5}$ and ${\cal{B}}(\psi(3686)\to\Xi(1530)^{0}\bar{\Xi}^{0}) = (0.53\pm0.04\pm0.03)\times10^{-5}$. Here, the first and second uncertainties are statistical and systematic, respectively. In addition, the parameter associated with the angular distribution for the decay $\psi(3686)\to\Xi(1530)^{0}\bar{\Xi}(1530)^0$ is determined to be $\alpha = 0.32\pm0.19\pm0.07$, in agreement with theoretical predictions within one standard deviation.