Effect of strong magnetic fields on neutral pion condensation in neutron star matter

We explore within the mean-field theory with TM1 parametrization the possibility of the pi(0) condensation under strong external magnetic fields in neutron star matter that includes sigma particles. At the magnetic field of B = 10(18) G, pi(0) does not condense. At B = 6 x 10(18) G, pi(0) condensation together with a partial stiffening of the matter equation of state occurs in the baryon number densities below 1 fm(-3). It is anticipated that the average magnetic field in the stellar interior does not exceed O(10(18)) G in a neutron star as massive as two times a solar mass.