Toward Realistic Treatment of Neutral Pion-Condensed State

Abstract

We describe several realistic treatments of the neutral pion (π 0 )-condensed state or ALS structure. Treatments we call «realistic» here aim to incorporate the effects from (1) the isobar Δ(1232), (2) the reduction of the OPE-tensor force in the short range due to ρ meson, (3) the central force due to «σ» and ω meson, and (4) the short-range correlations between baryons. We present the following approaches to take account of these effects, i.e., an OBEP one with a schematic short-range correlation, a reaction-matrix one and two kinds of effective interaction approach. The transition density ρ t (π 0 ) is found to be (2-3)ρ 0 in neutron matter and about 2.5 ρ 0 in symmetric nuclear matter (ρ t being the nuclear density)