Landau-Migdal parameters, g'(sub NN) and g'(sub N Delta)

Abstract

Landau-Migdal parameters for nucleon-nucleon (g'(sub NN)), together with nucleon-Delta(g'(sub N Delta)) and Delta-Delta(g'(sub Delta Delta)) couplings, play an important role in spin dependence structure of nuclei. The parameters were evaluated with the excitation energy and Gamow-Teller (GT) state strength which were obtained from recent experiment. The calculation was carried out by the quark model with spin and isospin operators summed up of 3 quarks of baryon. By using Nb-90 quenching value Q = 0.90 +/- 0.05 obtained from the experiment, then g'(sub N Delta) = 0.18 + 0.05g'(sub Delta Delta) was evaluated. When assuming g'(sub Delta Delta) is smaller than 1.0, then, an inequality relationship of 0.18 smaller than g'(sub N Delta) smaller than 0.23 can be obtained. Considering the excitation energy of GT state, an inequality relationship of 0.591 smaller than g'(sub NN) smaller than 0.594 can be evaluated.

核子-核子(g'(sub NN))、核子-Δ(g'(sub NΔ))、Δ-Δ(g'(sub ΔΔ))の結合のためのLandau-Migdalパラメータは核のスピン依存構造に重要な役割をもつため、これらのパラメータの評価を、最近得られた励起エネルギーとGamow-Teller(GT)状態の強さの実験データを用いて行った。計算はクォーク模型を使い、スピンおよびアイソスピン演算子はバリオン中の3個クォークの和をもって扱った。実験より求めたNb-90のクエンチング因子Q=0.90±0.05を用いて、g'(sub NΔ)=0.18+0.05g'(sub ΔΔ)と求めた。もしg'(sub ΔΔ)<1.0と仮定するならば0.18<g'(sub NΔ)<0.23となる。またGT状態の励起エネルギーの考慮から0.591<g'(sub NN)<0.594という結果を得た。