Dynamical relativistic corrections to the leptonic decay width of heavy quarkonia

F. Bissey; J.-J. Dugne; J.-F. Mathiot

doi:10.1007/s100520200920

EPJ

Dynamical relativistic corrections to the leptonic decay width of heavy quarkonia

F. Bissey^a, J.-J. Dugne^b and J.-F. Mathiot^c

Laboratoire de Physique Corpusculaire, Université Blaise-Pascal, CNRS/IN2P3, 24 avenue des Landais, 63177 Aubière Cedex, France

Received: 6 December 2001
Published online: 6 April 2002

Abstract

We calculate the dynamical relativistic corrections, originating from radiative one-gluon exchange, to the leptonic decay width of heavy quarkonia in the framework of a covariant formulation of light-front dynamics. Comparison with the non-relativistic calculations of the leptonic decay width of J = 1 charmonium and bottomonium S-ground states shows that relativistic corrections are large. Most importantly, the calculation of these dynamical relativistic corrections legitimate a perturbative expansion in α_s, even in the charmonium sector. This is in contrast with the ongoing belief based on calculations in the non-relativistic limit. Consequences for the ability of several phenomenological potentials to describe these decays are described.