Extraction of the Landau-Migdal Parameter from the Gamow-Teller Giant Resonance in Sn-132

The key parameter to discuss the possibility of the pion condensation in nuclear matter, i.e., the so-called Landau-Migdal parameter g', was extracted by measuring the double-differential cross sections for the (p, n) reaction at 216 MeV/u on a neutron-rich doubly magic unstable nucleus, Sn-132 with the quality comparable to data taken with stable nuclei. The extracted strengths for Gamow-Teller (GT) transitions from Sn-132 leading to Sb-132 exhibit the GT giant resonance (GTR) at the excitation energy of 16.3 +/- 0.4(stat) +/- 0.4(syst) MeV with the width of Gamma = 4.7 +/- 0.8 MeV. The integrated GT strength up to Ex = 25 MeV is S-GT(-) = 53 +/- 5(stat)(-10)(+11)(syst), corresponding to 56% of Ikeda's sum rule of 3(N - Z) = 96. The present result accurately constrains the Landau-Migdal parameter as g' = 0.68 +/- 0.07, thanks to the high sensitivity of the GTR energy to g'. In combination with previous studies on the GTR for Zr-90 and Pb-208, the result of this work shows the constancy of this parameter in the nuclear chart region with (N - Z)/A = 0.11 to 0.24 and A = 90 to 208.