The $\eta(2225)$ observed by the BES Collaboration

TL;DR

This paper investigates the decay widths of potential $s\bar{s}$ states to identify the nature of the observed $\eta(2225)$ meson, suggesting it is likely a $4 ^1S_0$ $s\bar{s}$ state based on decay width comparisons.

Contribution

The study applies the $^3P_0$ meson decay model to analyze the decay widths of $3 ^1S_0$ and $4 ^1S_0$ $s\bar{s}$ states, providing insights into the nature of the $\eta(2225)$ meson.

Findings

The $3 ^1S_0$ state has a width of about 438 MeV at 2.24 GeV.

The $4 ^1S_0$ state has a width of about 125 MeV at 2.24 GeV.

The $\eta(2225)$ is more consistent with the $4 ^1S_0$ $s\bar{s}$ state based on width comparisons.

Abstract

In the framework of the $^3P_0$ meson decay model, the strong decays of the $3 ^1S_0$ and $4 ^1S_0$ $s\bar{s}$ states are investigated. It is found that in the presence of the initial state mass being 2.24 GeV, the total widths of the $3 ^1S_0$ and $4 ^1S_0$ $s\bar{s}$ states are about 438 MeV and 125 MeV, respectively. Also, when the initial state mass varies from 2220 to 2400 MeV, the total width of the $4 ^1S_0$ $s\bar{s}$ state varies from about 100 to 132 MeV, while the total width of the $3 ^1S_0$ $s\bar{s}$ state varies from about 400 to 594 MeV. A comparison of the predicted widths and the experimental result of $(0.19\pm 0.03^{+0.04}_{-0.06})$ GeV, the width of the $\eta(2225)$ with a mass of $(2.24^{+0.03+0.03}_{-0.02-0.02})$ GeV recently observed by the BES Collaboration in the radiative decay $J/\psi\to\gamma\phi\phi\to\gamma K^+K^-K^0_SK^0_L$, suggests that it would be very difficult to identify the $\eta(2225)$ as the $3 ^1S_0$ $s\bar{s}$ state, and the $\eta(2225)$ seams a good candidate for the $4 ^1S_0$ $s\bar{s}$ state.