Strange quark matter within the Nambu-Jona-Lasinio model

Abstract

Equation of state of baryon rich quark matter is studied within the SU(3) Nambu-Jona-Lasinio model with flavour mixing interaction. Possible bound states (strangelets) and chiral phase transitions in this matter are investigated at various values of strangeness fraction S/3B. The model predictions are very sensitive to the ratio of vector (Gv) and scalar (Gs) coupling constants. At Gv/Gs=0.5 and zero temperature the maximum binding energy (about 15 MeV per baryon) takes place when strangeness fraction is about 0.4. Such strangelets are negatively charged and have typical life times of the order of 100 ns. Calculations are carried out also at finite temperatures. They show that bound states exist up to temperatures of about 15 MeV. The model predicts a first order chiral phase transition at finite baryon densities. The parameters of this phase transition are calculated as function of strangeness fraction.