The high density region of QCD in a large mass and chemical potential   model
  We study the high density region of QCD within an effective model obtained in the frame of the hopping parameter expansion. The model still acknowledges the sign problem peculiar to non-zero chemical potential, but it permits the development of refined algorithms which ensure a good overlap of the Monte Carlo ensemble with the true one. We review the main features of the model, including the most explicit form of the resumed expansion, and present calculations concerning the dependence of various observables on the chemical potential and on the temperature, in particular of the charge density and the diquark susceptibility, which may be used to characterize the various phases expected at high baryonic density. 
Roberto De Pietri and Alessandra Feo (Dip. di Fisica, Univ. di Parma),   Erhard Seiler (MPI fuer Physik, Muenchen) and Ion-O...