Direct reactions using few-body models

今天，核物理学家能够通过实验室专用加速器制造出具有非常反常的中子和质子组合的短寿命奇异原子核。计算和测量它们的新性质、结构和稳定性都是一个科学挑战。测试和改进我们对这些全新原子核的知识和理论预测的准确性是这项研究项目将为之做出贡献的长期目标。许多奇异原子核的结合很弱，因此可以准确地模拟为两个、三个或四个相互作用的粒子。这些粒子可以是单个核子，也可以是成团的核子。这样的动力学模型被称为少体模型。拟议的研究汇集了核反应和少体核结构模型专家，以继续正在进行的研究，包括研究生在三个领域的研究。它们是：(A)通过比较理论三体超球散射和R(反应)矩阵方法，研究三体结构中共振的描述以及它们的衰变方式；(B)扩展计算束缚三体系统的数学和计算方法，以允许计算四体系统；以及(C)发展(p，2p)核子敲除反应的理论，以了解未来的实验。在这些反应中，质子从原子核中移除，允许探测被移除的核子的量子力学状态，从而带来原始原子核的结构信息。

Today nuclear physicists are able to produce short-lived exotic nuclei with very abnormal neutron and proton combinations by using dedicated, laboratory-based accelerators. It is a scientific challenge both to calculate and measure their novel properties, structures and stability. Testing and improving our knowledge and the accuracy of the theoretical predictions for these completely new nuclei is a long term goal to which this research project will contribute. Many exotic nuclei are rather weakly bound and can thus be accurately modelled as two-, three- or four- interacting particles. These particles can be individual nucleons or bound clusters of nucleons. Such dynamical models are referred to as few-body models. The proposed research brings together nuclear reactions and few-body nuclear structure model experts to continue ongoing research, including that of research students, in three areas. These are (a) to examine the description of resonances in three-body structures, and the way they then decay, by comparing the theoretical three-body hyperspherical scattering and R(reaction)-matrix methods, (b) to extend the mathematical and computational methods for calculations of bound three-body systems to allow calculations four-body systems, and (c) to develop the theory of the (p,2p) nucleon-knockout reaction to understand future expeiments. These reactions, in which a proton is removed from a nucleus, allows the quantum mechanical state of the removed nucleon to be probed, and hence brings information of the structure of the original nucleus.