| 摘要: |
We aim to explore the production rate of the pseudoscalar glueball in J/psi radiative decay by lattice quantum chromodynamics in quenched approximation. The calculation is performed on three anisotropic lattices with the spatial lattice spacing ranging from 0.222(2) fm to 0.110(1) fm. As a calibration of some systematical uncertainties, we first extract the M1 form factor (V) over cap (0) of the process J/psi -> gamma eta(c) and get the result (V) over cap (0) = 1.933(41) in the continuum limit, which gives the partial width Gamma(J/psi -> gamma eta(c)) = 2.47(11) keV. These results are in agreement with that of previous lattice studies. As for the pseudoscalar glueball G(0)-+, its mass is derived to be 2.395(14) GeV, and the form factor (V) over cap (0) of the process J/psi -> gamma G(0)-+ is determined to be (V) over cap (0) = 0.0246(43) after continuum extrapolation. Finally, the production rate of the pseudoscalar glueball is predicted to be 2.31(90) x 10(-4), which is much smaller than that of conventional light q (q) over bar eta states. After the subtraction of the phase space factor, the couplings of J/psi X gamma are similar where X stands for eta states and the pseudoscalar glueball. Possibly, the U-A(1) anomaly plays an important role for the large couplings of gluons to the flavor singlet eta states in J/psi radiative decays. |
