EFFECTIVE GLUON MASS AND THE DETERMINATION OF ALPHA(S) FROM J/PSI AND Y-BRANCHING RATIOS

The phase space modification associated with a nonvanishing effective mass for the primary gluons, M(g)=0.66+/-0.08 GeV for the J/psi and M(g)=1.17+/-0.08 GeV for the gamma, is shown to be crucial for a consistent description of the photon spectrum from their radiative decays and for the determination of alpha(s) from the recent, precise quarkonia decay branching ratios. In this approach, the role of the relativistic corrections is marginal and, after applying the M(g)-dependent corrections, a good agreement is obtained with the relative perturbative running, alpha(s)(m(c))similar to 0.30+/-0.02 and alpha(s)(m(b))similar to 0.21+/-0.01, and with the extra-polation from deep inelastic scattering. On the other hand, the M(g)=0, the analysis of the experimental c (c) over bar and b (b) over bar quarkonia branching ratios is consistent with the same effective value of the strong interaction coupling constant alpha(s)(eff)similar to 0.185+/-0.010. By assuming a ''genuine,'' i.e., process-independent, gluon mass (similar to 1.2 GeV or higher) to be dynamically generated one predicts a strong suppression of the gluon splitting process at the J/psi and the hadronic final states should be mainly produced via gluon fusion into light q (q) over bar pairs thus effectively reducing the fitted value of M(g) from the photon spectrum in J/psi-->gamma+X. The gluon fusion mechanism allows us to explain the structure of the hadronic final states observed in J/psi decays and their close similarity to the continuum e(+)e(-)-->hadrons annihilation at comparable center of mass energies.