EFFECTS OF DELTA-DEGREES OF FREEDOM ON QUARK CONDENSATE IN HOT AND DENSE MATTER

The relativistic mean-held theory is applied to study the quark conden sate systematically in nuclear matter at zero and finite temperature i n terms of the relative importance of delta degrees of freedom. Calcul ations have included the high-order contributions to quark condensate in nuclear medium due to the baryon-baryon interactions. Numerical res ults are presented for the nuclear density up to five times larger tha n the normal density and temperature up to 120 MeV. It is found that t he delta resonance in nuclear matter can cause substantial decreases t o in-medium quark condensate.