The radiative decay of $J/\psi$ into a pure gauge tensor glueball is studied in the quenched lattice QCD formalism. With two anisotropic lattices, the multipole amplitudes $E_1(0)$, $M_2(0)$, and $E_3(0)$ are obtained to be 0.114(12)(6) GeV, $-0.011(5)(1)\mathrm{GeV}$, and 0.023(8)(1) GeV, respectively. The first error comes from the statistics, the $Q^2$ interpolation, and the continuum extrapolation, while the second is due to the uncertainty of the scale parameter $r_0^{-1}=410(20)\mathrm{MeV}$. Thus, the partial decay width $\Gamma (J/\psi \to \gamma G_{2^{++}})$ is estimated to be 1.01(22)(10) keV, which corresponds to a large branch ratio $1.1(2)(1)\times {10}^{-2}$. The phenomenological implication of this result is also discussed.

• Received 23 April 2013

DOI:https://doi.org/10.1103/PhysRevLett.111.091601