Observation of the decays $\chi_{cJ} \to \phi \phi \eta$

TL;DR

This study reports the first observation and measurement of branching fractions for the decays of $oldsymbol{ ext{chi}_{cJ}}$ into $oldsymbol{ ext{phi phi eta}}$ using a large data sample from BESIII, with no significant intermediate structures found.

Contribution

First observation and precise measurement of $ ext{chi}_{cJ} o ext{phi phi eta}$ decays, expanding understanding of charmonium decay modes.

Findings

Branching fractions measured for $ ext{chi}_{c0}$, $ ext{chi}_{c1}$, and $ ext{chi}_{c2}$ decays.

No significant intermediate resonant structures observed.

Large data sample enabled statistically significant observations.

Abstract

Using a data sample of $(448.1\pm2.9)\times10^{6}$ $\psi(3686)$ decays collected by the BESIII detector at the Beijing Electron Positron Collider (BEPCII), we observe the decays $\chi_{cJ}\to \phi\phi\eta~(J=0,~1,~2)$, where the $\chi_{cJ}$ are produced via the radiative processes $\psi(3686)\to\gamma\chi_{cJ}$. The branching fractions are measured to be $\mathcal B(\chi_{c0}\to\phi\phi\eta)=(8.41\pm0.74\pm0.62)\times10^{-4}$, $\mathcal B(\chi_{c1}\to\phi\phi\eta)=(2.96\pm0.43\pm0.22)\times 10^{-4}$, and $\mathcal B(\chi_{c2} \to \phi\phi\eta)=(5.33\pm0.52\pm0.39) \times 10^{-4}$, where the first uncertainties are statistical and the second are systematic. We also search for intermediate states in the $\phi\phi$ or $\eta\phi$ combinations, but no significant structure is seen due to the limited statistics.