Radiative transitions among the vector and scalar heavy quarkonium   states with covariant light-front quark model
  In this article, we study the radiative transitions among the vector and scalar heavy quarkonium states with the covariant light-front quark model. In calculations, we observe that the radiative decay widths are sensitive to the constituent quark masses and the shape parameters of the wave-functions, and reproduce the experimental data with suitable parameters. 
Zhi-Gang Wang
hep-ph