Spin-isospin responses of nuclei — Gamow-Teller response functions and pionic response functions in the quasi-elastic scattering region

Abstract

Recent elaborate experiments of ( p , n ) and ( n , p ) reactions provide detailed information about spin-isospin responses of nuclei at two different energy-momentum regions. One is the Gamow-Teller (GT) response function at small energy and momentum transfers ( ω , q ) , and the other is the pionic response functions in the quasi-elastic scattering (QES) region at relatively large q ( ≈ 1.7 ) fm −1 . The measured GT strength distributions and isovector spin-longitudinal cross sections ID q in the QES region are analyzed in the same theoretical framework of the distorted wave impulse approximation with the continuum random phase approximation (CRPA) including the Δ-isobar degree of freedom. As the effective interactions for the CRPA, the π + ρ + g ′ model interactions are utilized. The Landau-Migdal parameters g N N ′ and g N Δ ′ , which specify the effective interactions, are determined for the two different ( ω , q ) regions.