Dilepton Production in the Central Rapidity Region

Generalized Boltzmann approximation of the phase-space distribution function of quarks in the quark phase and of pions in the hadron phase, adopted by previous authors, to a complete expression, the dilepton production in Bjorken's (1+1) dimensional scaling expansion system is studied. We find that the dilepton production is heightened, and the shape of the characteristic dilepton dietribution for the quark matter formation in ultrarelativistic nucleus-nucleus collisions is significantly changed.