Lattice Study of Radiative $J/\psi$ Decay to a Tensor Glueball

TL;DR

This study uses lattice QCD to analyze the radiative decay of J/psi into a tensor glueball, providing quantitative decay amplitudes and widths, and discussing implications for particle physics.

Contribution

First lattice QCD calculation of J/psi radiative decay into a tensor glueball with detailed amplitude and width estimates.

Findings

Decay width estimated at 1.01 keV

Branch ratio approximately 1.1%

Provides multipole amplitude values

Abstract

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 mutlipole amplitudes E_1(0), M_2(0) and E_3(0) are obtained to be 0.114(12)(6)GeV, -0.011(5)(1)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) MeV. Thus the partial decay width $\Gamma(J/\psi\rightarrow \gamma G_{2^{++}})$ is estimated to be 1.01(22)(10) keV which corresponds to a large branch ratio 1.1(2)(1)x10^{-2}. The phenomenological implication of this result is also discussed.