| Project/Area Number |
12640294
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | Hosei University |
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Principal Investigator |
ICHIMURA Munetake Hosei University, Faculty of Computer and Information Sciences, Professor, 情報科学部, 教授 (10012436)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
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| Keywords | Spin-isospin modes / Response function / Quasi-elastic scattering / Continuum RPA / DWIA / Two step process / Landau-Migdal parameter / (p,n) reaction / スピン応答関数 / (p, n)反応 / ガモフ・テラー遷移 / ランダウ・ミグダル・パラメータ / パイオン凝縮 / 偏極移行係数 / DWIA / 連続RPA / ランダウミグダルパラメータ / 有効質量 |
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| Research Abstract |
We developed a theoretical framework to analyse the spin observables of the charge exchange quasi-elastic scattering, which gives us information of the isovector spin response functions. The framework consists of three aspects: (1) Nuclear response functions are calculated by the continuum random phase approximation, which takes into account the radial dependent effective mass and the spreading widths of the particles and the holes, and include the Δ isobar; (2) One-step process of the reaction is calculated by the distorted wave impulse approximation; and (3) the two-step processes are estimated by the plane wave approximation. In the calculition of the one- and two-step processes, the above mentiond response functions are used.
Using this theoretical framework we analysed ^<12>C, ^<40>Ca(p^^→, n^^→) reactions at 350 and 500MeV at various angles. The spin-longitudinal response functions were well reproduced, and consistent with long predicted enhancement. This is the first evidence of a precusor phenomenon of the pion condensation. We evaluated the Landau-Migdal parameters to reproduce the data. We found that the often used universality ansatz does not hold, and the obtained values are consitent with those obtaied from the Gamov-Teller transition strength distribution. Reproduction of the transverse response functions was much improved but not yet satisfactory.
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