Nucleon Charge-Exchange Reactions at Intermediate Energy
Nucleon Charge-Exchange Reactions at Intermediate Energy
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DOI：
10.1007/0-306-47073-x_1
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
W. Alford;B. Spicer
中科院分区：
文献类型：
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作者：
W. Alford;B. Spicer
几十年来，伽莫夫-特勒（GT）或自旋翻转，同位旋翻转相互作用一直是核物理研究的许多重要领域的核心。它首先被确认为β衰变中弱相互作用的一个组成部分，在氢聚变反应的初始步骤中起着关键作用，导致核合成，并在电子捕获反应中导致恒星坍缩和超新星形成。它还产生了一种重要的核激发模式，伽莫夫-特勒巨共振（GTGR）。在过去的十年中，大量的兴趣集中在GTGR上，既作为核巨共振的一个例子，也作为核物理新方向的可能指标，包括核结构的通常壳模型之外的影响，并涉及核子本身的子结构。人们也早就认识到，强核子-核子相互作用包括GT分量。这在40多年前的低能（p，n）反应中得到了证明，当时人们清楚地认识到了允许的β衰变率和（p，n）反应截面之间的联系。人们对这一领域的兴趣很高，但直到大约15年前，用于与大量理论推测进行比较的数据库非常有限。这种情况随着密歇根州立大学的演示而发生了戏剧性的变化，不久之后在印第安纳州大学回旋加速器设施（IUCF）更令人信服地证明，中等能量的（p，n）反应为研究对应于β衰变的GT跃迁（通常称为GT跃迁）提供了定量工具。随着新的实验设备的发展，对应于β+衰变的p）反应很快变得可行，首先是在TRIUMF，然后是在LAMPF和乌普萨拉。这样就有可能对GT-和GT+巨共振进行系统的研究，并充分研究非常强大的GT求和规则的含义。这篇评论介绍了该领域的中间能量电荷交换反应的时候，大量的实验数据已经积累，并可用于与理论模型进行比较。这也是核物理领域令人兴奋的时刻，GTGR为有关核结构中亚核子自由度重要性的新想法提供了重要的试验场。这里的介绍反映了一个实验主义者的观点;最近奥斯特费尔德[1]从理论的角度对这个领域作了一个很好的评论。这两次审查可视为相辅相成。
For many decades, the Gamow–Teller (GT) or spin-flip, isospin-flip interaction has been central to many important areas of nuclear physics research. First identified as a component of the weak interaction in allowed beta-decay, it plays a critical role in the initial step of the hydrogen fusion reaction leading to nucleosynthesis, and in the electron capture reactions leading to stellar collapse and supernova formation. It also gives rise to an important mode of nuclear excitation, the Gamow–Teller giant resonance (GTGR). Over the past decade, a great deal of interest has focussed on the GTGR both as an example of a nuclear giant resonance, and as a possible indicator of new directions in nuclear physics encompassing effects beyond the usual shell model of nuclear structure, and involving the substructure of the nucleons themselves. It has also long been recognized that the strong nucleon-nucleon interaction includes a GT component. This was demonstrated in low energy (p, n) reactions over forty years ago, and the connection between allowed beta-decay rates and (p, n) reaction cross sections was clearly recognised at that time. Interest in this field was high, but until about fifteen years ago there was a very limited data base for comparison with the large body of theoretical speculation. This situation changed dramatically with the demonstration at Michigan State University, and soon after more convincingly at the Indiana University Cyclotron Facility (IUCF), that the (p, n) reaction at intermediate energies provided a quantitative tool for the study of GT-transitions corresponding to β–-decay, usually referred to as GT–transitions.Comparable studies of (n, p) reactions corresponding to β+ decay soon became feasible with the development of new experimental facilities first at TRIUMF and then at LAMPF and Uppsala. Thus it became possible to carry out systematic studies of both GT–and GT+ giant resonances and to investigate fully the implications of the very powerful GT sum rule. This review describes the field of intermediate energy charge-exchange reactions at a time when a large body of experimental data has been accumulated and is available for comparison with theoretical models. It has also been a time of excitement in the field of nuclear physics, with the GTGR providing an important testing ground for new ideas about the importance of sub-nucleon degrees of freedom in nuclear structure. The presentation here reflects an experimentalist’s viewpoint; an excellent review of the field from a theoretical viewpoint has recently been given by Osterfeld [1]. The two reviews may be regarded as complementary.