Suppression of Dilepton in Expanding Hot Baryon-Rich Quark-Gluon Matter

With the increase of the initial baryon density, the dilepton production in invariant masses between 2m_π and 1 GeV is shown to be suppressed and an abnormal peak of the dilepton spectrum appears near the invariant mass 0.75 GeV if a baryon-rich quark-gluon matter was formed in the ultrarelativistic nucleus-nucleus collision. These predictions are important for several large-scale experiments at CERN and Brookhaven.