Observation of $J/\psi \rightarrow p\bar{p}a_{0}(980)$ at BESIII

TL;DR

This paper reports the first observation of the decay process $J/a... to four-body final states, providing new insights into $a_0(980)$ production and $J/a... decay dynamics.

Contribution

First observation of $J/\psi \rightarrow p\bar{p}a_0(980)$ with measured branching fraction, enhancing understanding of meson production near threshold.

Findings

Observation significance of 6.5 sigma

Branching fraction measured as (6.8±1.2±1.3)×10^{-5}

Provides data on $a_0(980)$ coupling to $p\bar{p}$

Abstract

Using $2.25\times10^{8}$ $J/\psi$ events collected with the BESIII detector at the BEPCII storage rings, we observe for the first time the process $J/\psi\rightarrow p\bar{p}a_{0}(980)$, $a_{0}(980)\rightarrow \pi^{0}\eta$ with a significance of $6.5\sigma$ ($3.2\sigma$ including systematic uncertainties). The product branching fraction of $J/\psi\rightarrow p\bar{p}a_{0}(980)\rightarrow p\bar{p}\pi^{0}\eta$ is measured to be $(6.8\pm1.2\pm1.3)\times 10^{-5}$, where the first error is statistical and the second is systematic. This measurement provides information on the $a_{0}$ production near threshold coupling to $p\bar{p}$ and improves the understanding of the dynamics of $J/\psi$ decays to four body processes.