Partial Wave Analyses of $J/\psi\to\gamma K^+K^-$ and $\gamma K^0_SK^0_S$

TL;DR

This paper reports on partial wave analyses of $J/\psi$ radiative decays to $K^+K^-$ and $K^0_SK^0_S$, identifying resonances like $f'_2(1525)$ and $f_0(1710)$ with detailed measurements of their properties.

Contribution

It provides the first detailed partial wave analysis of these decay channels using a large data sample, revealing the properties of specific scalar and tensor mesons.

Findings

Identification of $f'_2(1525)$ and $f_0(1710)$ resonances.

Precise measurements of the $f_0(1710)$ mass and width.

Determination of helicity amplitude ratios for $f'_2(1525)$.

Abstract

Results are presented on $J/\psi $ radiative decays to $K^+K^-$ and $K^0_SK^0_S$ based on a sample of 58M $J/\psi$ events taken with the BES II detector. A partial wave analysis is carried out using the relativistic covariant tensor amplitude method in the 1-2 GeV mass range. There is conspicuous production due to the $f'_2(1525)$ and $f_0(1710)$. The latter peaks at a mass of $1740\pm 4^{+10}_{-25}$ MeV with a width of $166{^{+5}_{-8}}{^{+15}_{-10}}$ MeV. Spin 0 is strongly preferred over spin 2. For the $f'_2(1525)$, the helicity amplitude ratios are determined to be $x^2 = 1.00\pm0.28^{+1.06}_{-0.36}$ and $y^2 = 0.44\pm{0.08}^{+0.10}_{-0.56}$.