Coexistence of color superconductivity and chiral symmetry breaking within the NJL modelD. Blaschke1, 2, M.K. Volkov2 and V.L. Yudichev2
1 Fachbereich Physik, Universität Rostock, D-18051 Rostock, Germany
2 Joint Institute for Nuclear Research, 141980 Dubna, Russian Federation
(Received: 3 January 2003 / Published online: 24 April 2003)
The phase diagram for quark matter is investigated within a simple Nambu-Jona-Lasinio model without vector correlations. It is found that the phase structure in the temperature-density plane depends sensitively on the parametrization of the model. We present two schemes of parametrization of the model where, within the first one, a first-order phase transition from a phase with broken chiral symmetry to a color superconducting phase for temperatures below the triple point at Tt= 55 MeV occurs, whereas for the second one a second-order phase transition for temperatures below Tt = 7 MeV is found. In the latter case, there is also a coexistence phase of broken chiral symmetry with color superconductivity, which is a new finding within this class of models. Possible consequences for the phenomenology of the QCD phase transition at high baryon densities are discussed.
11.30.Rd - Chiral symmetries.
12.38.Lg - Other nonperturbative calculations.
11.10.Wx - Finite-temperature field theory.
25.75.Nq - Quark deconfinement, quark-gluon plasma production, and phase transitions.
© Società Italiana di Fisica, Springer-Verlag 2003