Observation of $\chi_{cJ}(J=0,1,2)\rightarrow p\bar{p}\eta\eta$

TL;DR

This paper reports the first observation of the decays of $ ext{chi}_{cJ}$ states into $par{p} ext{eta} ext{eta}$ using a large dataset, measuring their branching fractions with high statistical significance.

Contribution

First observation of $ ext{chi}_{cJ} o par{p} ext{eta} ext{eta}$ decays and measurement of their branching fractions using BESIII data.

Findings

Branching fractions measured for $ ext{chi}_{c0,1,2}$ decays.

Signals for $ ext{chi}_{cJ}$ decays have significance > 5$\sigma$.

No resonant structures found in $par{p}$ and $p ext{eta}/ar{p} ext{eta}$ systems.

Abstract

Using $(2712.4\pm14.3)\times10^6$ $\psi(3686)$ events collected by the BESIII detector operating at the BEPCII storage ring, the decays $\chi_{cJ}(J=0,1,2)\rightarrow p\bar{p}\eta\eta$ are observed for the first time through the radiative transition $\psi(3686)\to\gamma\chi_{cJ}$. The statistical significances for $\chi_{cJ}$ signals are all larger than 5$\sigma$. The branching fractions of $\chi_{c0,1,2}\to p\bar{p} \eta\eta$ are determined to be $({5.75 \pm 0.59 \pm 0.42}) \times 10^{-5}$, $({1.40 \pm 0.33 \pm 0.17}) \times 10^{-5}$, and $({2.64 \pm 0.40 \pm 0.27}) \times 10^{-5}$, respectively, where the first uncertainties are statistical and the second systematic. No evident resonant structures are found in the $p\bar{p}$ and $p\eta/\bar{p}\eta$ systems.