Neutron Star Matter Including Delta Isobars

In this paper a new phase structure of neutron star matter includingnucleons and delta isobars is presented. Particle fractions populated andpion condensations in neutron star matter are investigated in this model. Theexistence of the pion condensations can postpone the appearance of deltaisobars. We found that both the pion condensation and reduce of the ratio ofdelta isobar to nucleons couplings can soften the corresponding equation ofstate. The maximum masses and their corresponding radii of neutron stars arecalculated, and the obtained values are in observational region.