Gamow-Teller strength in the continuum and quenching problem

H. Sakai, T. Wakasa, H. Okamura, T. Nonaka, T. Ohnishi, K. Yako, K. Sekiguchi, S. Fujita, Y. Satou, H. Otsu, T. Uesaka, S. Ishida, N. Sakamoto, M. B. Greenfield, K. Hatanaka

研究成果: ジャーナルへの寄稿学術誌査読

10 被引用数 (Scopus)


Differential cross sections at θlab = 0.0° 12.3° and a complete set of polarization transfer observables at θlab = 0.0° are measured for the 90Zr(p, n) reaction at Tp = 295 MeV. A multipole decomposition (MD) technique is applied to the cross sections to extract partial cross sections σL with L=0, 1, 2, and 3 contributions. A significant amount of σL=0 is found in the highly excited continuum region. After subtracting the estimated iso-vector spin-monopole strength from σL=0, the Gamow-Teller (GT) strength B(GT) is deduced to be Sβ- = ∑ B(GT) = 28 ± 1.6 ± 5.4. The total spin transfer ∑(0°) which is independent of the nuclear reaction mechanisms such as the effective nncleon-nucleon interaction or distortions is derived from the complete set of polarization transfer observables. It is close to unity up to 50 MeV excitation indicating the strong spin-flip character of the continuum. By using the relation between the polarization transfer observables the fractions of natural-parity and unnatural-parity transitions are also obtained and the dominance of unnatural-parity transitions in the continuum is found. These results are consistent with those derived from the MD analysis. The Sβ- - Sβ+ value is 27.1 and this is 90% of Ikeda's sum rule value of 3(N - Z)=30. Consequently it is concluded that the quenching of the GT strength is small and the quenching mechanism due to the ΔN admixture seems to play a minor role.

ジャーナルNuclear Physics A
出版ステータス出版済み - 3月 29 1999

!!!All Science Journal Classification (ASJC) codes

  • 核物理学および高エネルギー物理学


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