${\chi }_{c0}$ and ${\chi }_{c2}$ decays into $\eta \eta$, $\eta {\eta }^{\prime }$, and ${\eta }^{\prime }{\eta }^{\prime }$ final states

Using a sample of $3\times {10}^6$ $\psi (2S)$ decays collected by the CLEO III and CLEO-c detector configurations, we present results of a study of ${\chi }_{c0}$ and ${\chi }_{c2}$ decays into $\eta \eta$, $\eta {\eta }^{\prime }$, and ${\eta }^{\prime }{\eta }^{\prime }$ final states. We find $B({\chi }_{c0}\to \eta \eta )=(0.31\pm 0.05\pm 0.04\pm 0.02)\%$, $B({\chi }_{c0}\to \eta {\eta }^{\prime })<0.05\%$ at the 90% confidence level, and $B({\chi }_{c0}\to {\eta }^{\prime }{\eta }^{\prime })=(0.17\pm 0.04\pm 0.02\pm 0.01)\%$. We also present upper limits for the decays of ${\chi }_{c2}$ into these final states. These results give information on the decay mechanism of ${\chi }_c$ states into pseudoscalars.

Figure 1

Invariant mass distributions for (a) $\eta \eta$, (b) $\eta {\eta }^{\prime }$, and (c) ${\eta }^{\prime }{\eta }^{\prime }$. The fits are described in the text.