BARYON DENSITY CONTRAST IN A QUARK-HADRON PHASE-TRANSITION IN THE EARLY UNIVERSE

We study the baryon density contrast between the quark-gluon and hadro n phases during the deconfinement phase transition in the early univer se. The quark-gluon phase is treated perturbatively to order g(2) in t he quantum-chromodynamics (QCD) coupling constant and by keeping the f inite masses for the s and c quarks. In the hadronic phase we have inc luded the finite size volume corrections for the hadrons and have acco unted for repulsive interaction by parameterizing the mean field poten tial energy. We have also considered an exponential mass spectrum with hard-core repulsive potential of the Hagedorn type for the hadron gas and find that the repulsive mean field potential, with or without exc luded volume correction, seems to stabilize the pressure and baryon de nsity contrast R when compared to only the excluded volume correction.