Formulation of two-photon and two-gluon decays of pseudoscalar mesons in a relativistic bound-state calculation

We formulate a relativistic bound-state calculation of the decay of (0-+) mesons into two gluons or two photons. The decays of c, b, and b are calculated and a value of s deduced from the total width of c. The calculated value for c2 is in agreement with experiment. The decays of 2 and 2 are calculated and by comparison with experiment and the bound on 2, restrictions are placed on the X, Y, X, and Y mixing coefficients of Rosner. The comparison with the Schrödinger-equation calculations shows that the inclusion of relativistic propagators spreads out the annihilations so that they do not occur at r=0. This suppresses the 2S and higher-level decays, with the greatest suppression for the lightest quarks.