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Exotic clusters accessed via resonant scattering

通过共振散射访问奇异簇

基本信息

批准号：
EP/E006302/1
负责人：
Martin Freer
金额：
$ 54.79万
依托单位：
University of Birmingham
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2006
资助国家：
英国
起止时间：
2006 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FE006302%2F1
关键词：
Exotic clusters accessed via resonant

项目摘要

The concept of the nucleus that is held by many, is of a tightly knit assembly of protons and neutrons, largely spherical and broadly featureless. But just like most things we learn at school the reality is much different. The nucleus is a rather dynamic environment in which the protons and neutrons move in quantized orbits at a sizable fraction of the speed of light. It is these dynamics that are of prime importance when it comes to the determination of the structural properties of the nucleus. Nucleons in the same orbit have large spatial overlaps with each other, and thus interact much more strongly than the mean of the interactions with other nucleons. If two protons and two neutrons (the spins being anti-aligned for identical particles) are in the same orbit, then the spatial overlap of a quartet of particles is maximised, and an alpha-particle emerges from the resulting correlations. In nature, the free alpha-particle, or helium nucleus, is rather robust / it has a very high binding energy / and thus within the confines of the nucleus, under the right conditions, preformed alpha-particles can appear. This in itself is not remarkable, but it is when the nucleus condenses entirely into alpha-particles! For example, certain states in 12C and 16O have been described in terms of a Bose alpha-particle gas. This proposal uses a resonant scattering technique, where alpha-cluster states are formed in collisions between a helium gas and a projectile to examine three classes of states in light nuclei that are predicted to have a truly remarkable structure; (i) Bose-alpha-gas states in 16O and 20Ne, (ii) alpha-particle states in which neutrons are exchanged between the clusters / the nuclear analog of atomic molecules, (iii) three centred cluster structures. All three areas are of key importance in the field of nuclear clustering and have direct links with atomic phenomena.

许多人所持有的原子核的概念是质子和中子紧密结合的集合体，大部分是球形的，没有什么特征。但就像我们在学校学到的大多数东西一样，现实情况大不相同。原子核是一个相当动态的环境，其中质子和中子以相当大的光速在量子化轨道上运动。在确定原子核的结构性质时，这些动力学是最重要的。在同一轨道上的核子彼此有很大的空间重叠，因此相互作用比与其他核子的平均相互作用强得多。如果两个质子和两个中子（对于相同的粒子，自旋是反对齐的）在同一轨道上，那么四重粒子的空间重叠最大化，并且从由此产生的相关性中出现α粒子。在自然界中，自由α粒子或氦核是相当坚固的/它具有非常高的结合能/因此在核的范围内，在适当的条件下，可以出现预先形成的α粒子。这本身并不值得注意，但当原子核完全凝聚成α粒子时，这是值得注意的！例如，12 C和16 O中的某些状态已经被描述为玻色α粒子气体。这一建议使用共振散射技术，在氦气和射弹之间的碰撞中形成α-团簇态，以检查轻核中被预测具有真正非凡结构的三类状态;（i）16 O和20 Ne中的玻色-α-气体状态，（ii）α-粒子状态，其中中子在原子分子的原子团簇/核模拟物之间交换，（三）三个中心集群结构。所有这三个领域在核成簇领域都是至关重要的，并且与原子现象有直接的联系。