Partial wave analysis of $J/\psi \to \gamma \eta^{\prime} \eta^{\prime}$

TL;DR

This paper performs a partial wave analysis of $J/1$ decays to identify resonances, reporting the properties of the dominant $f_0(2020)$ resonance with high significance and measuring its branching fractions.

Contribution

The study provides the first detailed partial wave analysis of $J/1 o \u03b3 \u03b5' \u03b5'$ decays, revealing the properties of the $f_0(2020)$ resonance.

Findings

Observation of $f_0(2020)$ with >25$7$ significance.

Measurement of the product branching fraction $(2.63 imes 10^{-4})$.

Determination of resonance masses and widths.

Abstract

Using a sample of $(10.09~\pm~0.04)\times10^{9} ~J/\psi$ events collected with the BESIII detector, a partial wave analysis of $J/\psi\to\gamma\eta^{\prime}\eta^{\prime}$ is performed. The masses and widths of the observed resonances and their branching fractions are reported. The main contribution is from $J/\psi\rightarrow\gamma f_0(2020)$ with $f_0(2020)\rightarrow\eta^{\prime}\eta^{\prime}$, which is found with a significance of greater than 25$\sigma$. The product branching fraction ${\cal B}\left(J/\psi\rightarrow\gamma f_0(2020)\right)\cdot{\cal B}\left(f_0(2020)\rightarrow\eta^{\prime}\eta^{\prime}\right)$ is measured to be $(2.63\pm0.06({\rm stat.})^{+0.31}_{-0.46}({\rm syst.}))\times10^{-4}$.