Rigorous arguments against current wisdoms in finite density QCD

QCD at finite chemical potential is analytically investigated in the region of large bare fermion masses. We show that, contrary to the general wisdom , the phase of the fermion determinant is irrelevant at zero temperature. H owever if the system is put at finite temperature, the contribution of the phase is finite. We also discuss on the quenched approximation and suggest that the origin of the failure of this approximation in finite density QCD could relay on the fundamental role that Pauli exclusion principle plays in this case. (C) 1999 Published by Elsevier Science B.V. All rights reserved .