Ab initio theory of light and medium mass nuclei

原子核是由质子和中子相互作用而形成的量子多体系统，这些作用力来源于量子色动力学的基本理论。从组成核子和核子间相互作用出发，精确地处理核子，一直是核物理学界长期追求的目标。******这个项目的目标是发展一个预测的从头算理论的核结构和核反应的轻和中等质量的核。这样的理论对于理解在像TRIUMF的ISAC这样的稀有同位素设施中研究的奇异核，对于理解对天体物理学很重要的核反应，对于理解对未来能源产生很重要的聚变反应，以及对核过程基本对称性的测试都是需要的。同时，它提供了作为这些计算输入的核子间相互作用质量的反馈，并最终有助于提高我们对核子-核子相互作用的认识，特别是对尚未完全理解的三核子相互作用的认识。******在这个提议中，我们结合了从头算核结构方法能够描述轻核的束缚状态与微观团簇方法开发描述核团簇的反应。由此产生的方法从质子和中子之间的核子相互作用出发，提供了对束缚态和非束缚态的统一描述。我们将运用这种方法来提高我们对外来核（如9He、11N或17C）的理解，来描述像11Be或11Li这样的晕核。利用包括三核子相互作用在内的最先进的核力，我们将计算天体物理学中重要的核反应速率，包括7Be(p,gamma)8B, 3He(4He,gamma)7Be, 2H(alpha,gamma)6Li和4He(nn,gamma)6He，这些反应在宇宙环境中发生的低能很难或不可能测量。我们还将研究与未来能源产生相关的核聚变反应，如3H(d,n)4He和11B(p, α)8Be。我们将研究6He的β衰变，这是超越标准模型的重要物理测试。我们也将为中质量原子核的从头算研究做出贡献，其中一个主要目标是改进中微子双β衰变矩阵元素的计算。最后，该项目的一个长期目标是计算对12C和16O的恒星合成至关重要的反应。可以预见，这些反应的理论理解的复杂性需要超大规模的计算

Atomic nuclei are quantum many-body systems made by protons and neutrons interacting with forces that originate from the fundamental theory of Quantum Chromo-Dynamics. The exact treatment of nuclei starting from the constituent nucleons and the inter-nucleon interactions among them has been a long-standing goal in nuclear physics. ******The goal of this project is to develop a predictive ab initio theory of nuclear structure and nuclear reactions for light and medium mass nuclei. Such a theory is needed for understanding of exotic nuclei investigated at rare isotope facilities like ISAC at TRIUMF, for understanding of nuclear reactions important for astrophysics, for understanding of fusion reactions important for the future energy generation as well as for the testing of fundamental symmetries in nuclear processes. At the same time, it provides a feedback on the quality of inter-nucleon iteractions used as input to these calculations and ultimately helps to improve our knowledge of the nucleon-nucleon interaction, and in particular of the still-not-completely-understood three-nucleon interaction. ******In this proposal, we combine an ab initio nuclear structure approach capable to describe bound states of light nuclei with a microscopic cluster method developed to describe reactions of nuclear clusters. The resulting method provides a unified description of both bound and unbound nuclear states starting from inter-nucleon interactions among protons and neutrons. We will apply this method to improve our understanding of exotic nuclei such as 9He, 11N, or 17C, to describe halo nuclei like 11Be or 11Li. Using state-of-the-art nuclear forces including the three-nucleon interaction, we will calculate rates of nuclear reactions important for astrophysics including 7Be(p,gamma)8B, 3He(4He,gamma)7Be, 2H(alpha,gamma)6Li and 4He(nn,gamma)6He that are difficult or impossible to measure at low energies at which these reactions occur in cosmic environments. We will also investigate fusion reactions such as 3H(d,n)4He and the aneutronic 11B(p,alpha)8Be relevant for future energy generation. We will study beta decay of 6He that is being measured as an important test of physics beyond the Standard Model. We will also contribute to ab initio investigatinos of medium mass nuclei with one of the major goals to improve calculations of the neutrinoless double-beta decay matrix elements. Finally, a long-term goal of this project is the calculation of reactions important for stellar synthesis of 12C and 16O. It is anticipated that the complexity of theoretical understanding of these reactions equires exa-scale computing.**