A Study of J/psi-->gamma gamma V(rho,phi) Decays with the BESII Detector

Abstract

Using a sample of $58\times 10^6$ $J/\ddot{I}ˆ$ events collected with the BESII detector, radiative decays $J/\ddot{I}ˆ\to {\hat{I}}^3{\hat{I}}^{3}V$, where $V=\ddot{I}$ or $\ddot{I}•$, are studied. A resonance around 1420 MeV/c${}^2$ (X(1424)) is observed in the ${\hat{I}}^3\ddot{I}$ mass spectrum. Its mass and width are measured to be $1424\pm 10(stat)\pm 11(sys)$ MeV/c${}^2$ and $101.0\pm 8.8\pm 8.8$ MeV/c${}^2$, respectively, and its branching ratio $B(J/\ddot{I}ˆ\to {\hat{I}}^{3}X(1424)\to {\hat{I}}^3{\hat{I}}^3\ddot{I})$ is determined to be $(1.07\pm 0.17\pm 0.11)\times 10^{-4}$. A search for $X(1424)\to {\hat{I}}^3\ddot{I}•$ yields a 95% C.L. upper limit $B(J/\ddot{I}ˆ\to {\hat{I}}^{3}X(1424)\to {\hat{I}}^3{\hat{I}}^3\ddot{I}•)<0.82\times 10^{-4}$.

10 pages, 5 figures, submitted to PLB