QUARK MATTER INSIDE NEUTRON-STARS IN AN EFFECTIVE CHIRAL MODEL

An effective chiral model which describes properties of a single baryo n predicts that the quark matter relevant to neutron stars, close to t he de-confinement density, is in a chirally broken phase. We find for the SU(2) model that pion-condensed up and down quark matter is prefer red energetically at neutron star densities. It exhibits spin ordering and can possess a permanent magnetization. The equation of state of q uark matter with chiral condensate is very well approximated by the ba g model equation of state with suitably chosen parameters. We study qu ark cores inside neutron stars in this model using realistic nucleon e quations of state. The biggest quark core corresponds to the second or der phase transition to quark matter. Magnetic moment of the pion-cond ensed quark core is calculated.