Gamow-Teller quenching value, Landau-Migdal parameter g′NΔ and pion condensation Original Research Article

We have carried out the 90Zr(p, n) and 90Zr(n, p) measurements at 300 MeV and succeeded to extract reliable Sβ− and Sβ+ values. We derived quenching factor (Q) of the Gamow-Teller strength in terms of the spin sum rule of Sβ− − Sβ+ = 3(N - Z) as Q = 0.87 ± 0.02(MDA) ± 0.04(IVSM) apart from the systematic uncertainty of ΔσGT <- 15%. The Landau-Migdal (LM) parameters representing a short-range correlation in an isospinspin channel are deduced from the Q value as g′NN = 0.60 ± 0.02 and g′NΔ = 0.28 ± 0.09. The critical density of the pion condensation is estimated to be ϱc ∼ 2ϱ0 which can be easily realized in the neutron stars. Recent observation of the surface temperature of the neutron star 3C58 supports the pionic cooling mechanism and consequently manifestation of the pion condensation in neutron stars.