Constituent quark masses from modified perturbative QCD

Abstract

A recently proposed modified perturbative expansion for QCD incorporating gluon condensation is employed to evaluate the quark and gluon self-energy corrections in the first approximations. The results predict mass values of 1/3 of the nucleon mass for the light quarks u, d, and s and a monotonously growing variation with the current mass. The only phenomenological input consists in that <G^2> is evaluated up to order g^2 as a function of the unique parameter C defining the modified propagator and then C is fixed to give a current estimate of <g^2 G^2>. The light quarks u and d result to be confined and the s, c, b and t ones show damped propagation modes, then suggesting a model for the large differences in stability between the nucleons and the higher resonances. The above properties of quark modes diverge from the fully confinement result following from the similar gluon propagator previously considered by Munczek and Nemirovski. On another hand, the condensate effects on the gluon self-energy furnish a tachionic mass shell as predicted by the Fukuda analysis of gluon condensation in QCD.