Nuclear Physics Seminar

We discuss phases of QCD at finite density and not high temperature,
below and above the chiral restoration phase transition.
In order to decide about the phase diagram of QCD, it is
necessary to understand origin of hadron mass, whether it is
entirely due to a quark condensate or not. We analyze excited
hadron spectra and show that mass of excited hadrons has mostly the
chiral-invariant origin. Then it is quite likely that above the chiral
restoration point at finite chemical potential, one would have a new phase
that represents a confining but chirally symmetric matter, rather
than a deconfining quark-gluon matter. We discuss some properties of
this matter and show that above the chiral restoration point it
represents a new kind of a fermi system, with a gap in the excitation
spectrum that increases with the chemical potential. This gap is
not due to condensation of the quasi Cooper pairs. It is only due
to such properties as confinement and manifest chiral symmetry at
the same time.