Radiative decays of Bc mesons in a Bethe-Salpeter model
  We evaluate the complete spectrum of the Bc mesons, below the open flavor BD threshold, in a Bethe-Salpeter model. We make predictions for the radiative decay widths of the Bc excited states. We compare our results with those of other models. 
A. Abd El-Hady, J. R. Spence and J. P. Vary