Dilepton invariant mass distribution in central rapidity region

The Boltzmann approximation of the phase-space distribution functions of quarks and of pions, previously adopted by the authors, is generalized to a complete expression. After calculating the density of particles from the temperature of the central rapidity region, the dilepton production in Bjorken's (1 + 1) dimensional scaling expansion system is studied. It is found that the generalized approximation distribution significantly changes the characteristic dilepton distribution for the prediction of the quark matter formation