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（t，3 He）和（3 He，t）反应的Gamow-Teller单位截面

Gamow-Teller Unit Cross Sections for (t,3He) and (3He,t) Reactions

G. Perdikakis, R. G. T. Zegers, Sam M. Austin, D. Bazin, C. Caesar, J. M. Deaven, A. Gade, D. Galaviz, G. Grinyer, C. J. Guess, C. Herlitzius, G. W. Hitt, M. E.… 展开作者

G. Perdikakis, R. G. T. Zegers, Sam M. Austin, D. Bazin, C. Caesar, J. M. Deaven, A. Gade, D. Galaviz, G. Grinyer, C. J. Guess, C. Herlitzius, G. W. Hitt, M. E. Howard, R. Meharchand, S. Noji, H. Sakai, Y. Shimbara, E. E. Smith, C. Tur

备注：
14 pages, 10 figures
发表信息：
Phys.Rev.C83:054614,2011
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摘要：

分别在115 $A$ MeV和140 $A$ MeV下，研究了（$t$，$^{3}$ He）和（$^{3}$ He，$t$）反应在线性动量转移消失时微分截面与Gamow-Teller跃迁强度（用\textit{unit cross section}（$\hatσ_{GT}$）表示）之间的比例关系，作为靶质量数的函数。关于质量数为$12\leq A\leq 120$的靶的现有（$^{3}$ He，$t$）和（$t$，$^{3}$ He）数据，用关于质子、氘、$^{6}$ Li和$^{12}$ C靶的新的和重新评估的（$t$，$^{3}$ He）数据进行了补充。结果发现，尽管在两个探针之间的束能量的小的差异，单位截面具有几乎相同的和简单的依赖于目标的质量数$A$，为$A\geq 12$：$\hatσ_{GT}=109/A^{0.65}$。研究了单位截面的运动学因子、畸变因子和有效自旋-同位旋转移核-核相互作用强度的因子分解。简单的唯象函数依赖于质量数$A$提取后两者。通过与平面和扭曲波玻恩近似计算的比较，发现对于涉及复合（$^{3}$ He，$t$）和（$t$，$^{3}$ He）探针的反应，使用短程近似的撞击交换对跃迁振幅的贡献导致高估了截面。

英文摘要：

The proportionality between differential cross sections at vanishing linear momentum transfer and Gamow-Teller transition strength, expressed in terms of the \textit{unit cross section} ($\hatσ_{GT}$) was studied as a function of target mass number for ($t$,$^{3}$He) and ($^{3}$He,$t$) reactions at 115 $A$MeV and 140 $A$MeV, respectively. Existing ($^{3}$He,$t$) and ($t$,$^{3}$He) data on targets with mass number $12\leq A\leq 120$ were complemented with new and reevaluated ($t$,$^{3}$He) data on proton, deuteron, $^{6}$Li and $^{12}$C targets. It was found that in spite of the small difference in beam energies between the two probes, the unit cross sections have a nearly identical and simple dependence on target mass number $A$, for $A\geq 12$: $\hatσ_{GT}=109/A^{0.65}$. The factorization of the unit cross sections in terms of a kinematical factor, a distortion factor and the strength of the effective spin-isospin transfer nucleus-nucleus interaction was investigated. Simple phenomenological functions depending on mass number $A$ were extracted for the latter two. By comparison with plane and distorted-wave Born approximation calculations, it was found that the use of a short-range approximation for knock-on exchange contributions to the transition amplitude results in overestimated cross sections for reactions involving the composite ($^{3}$He,$t$) and ($t$,$^{3}$He) probes.

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