High-precision measurements with the TITAN facility at ISAC-TRIUMF

宇宙中每一种已知化学元素的原子核都由质子和中子组成，而质子和中子又由夸克组成。这些组成粒子之间的相互作用决定了原子的稳定性和结构，因此也决定了地球和宇宙中元素及其同位素的丰度。关于原子稳定性的信息可以通过精确的实验获得，例如质量测量和衰变光谱学。原子的质量和由此推导出的结合能反映了所有亚原子相互作用;因此，它的测量使得有可能确定这种相互作用如何作为中子和质子数及其比率的函数。随着放射性离子束（RIB）设施的出现，对核子如何相互作用的详细研究已经成为可能，现在可以获得大约3500种核素。在这些设施中，TRIUMF的ISAC（同位素分离器和加速器）已成为领导者，不断提高越来越多的奇异RIB的可用性，即质子-中子比越来越不对称。与此同时，理论方法也取得了进展。核壳模型的非凡成功已被建立并扩展到解释高度奇异核中的意外现象。与此同时，其他方法依赖于量子染色体动力学（QCD）的重大进展，从第一性原理描述核相互作用。这些巨大的理论收益导致了详细的预测，本提案将对其进行研究。TITAN质谱仪用于进行高精度测量，以研究超允许β衰变和同位旋对称性。该研究计划包括对核结构的研究，从幻数的演变到三体效应和晕等奇异结构。这些精确的测量支持了研究核天体物理学所需的核物理学，以及理解宇宙中化学元素演化的探索。本文所述的所有科学调查都是可能的，因为TITAN设施的完善和尖端性能与ISAC-TRIUMF具有竞争力甚至前所未有的数量和质量的相关核素产量相结合。此外，ARIEL（高级稀有同位素实验室）的快速到来将使现有的实验机会增加两倍，并提供新的RIBs。因此，世界一流和独特的TITAN计划利用了质量测量和阱内衰变光谱的非凡实验机会，并利用了对TITAN设施的重大投资以及相关技能和技术的发展。

The atomic nucleus of every known chemical element in the Universe consists of protons and neutrons, which in turn are composed of quarks. The interaction among these constituent particles is responsible for the stability and structure of the atom and, therefore, the resultant abundances of the elements and their isotopes on Earth and in the Universe. Information about the stability of atoms can be gained through precision experiments, such as mass measurements and decay spectroscopy. The mass of an atom and, via it, the deduced binding energy reflect all subatomic interactions; thus, its measurement makes it possible to identify how that interaction behaves as a function of neutron and proton number as well as their ratio. Detailed studies of how nucleons interact have been made possible with the advent of radioactive-ion-beam (RIB) facilities, which now provide access to about 3500 nuclides. Of such facilities, ISAC (Isotope Separator and ACcelerator) at TRIUMF has emerged as a leader, ever improving availability of increasingly exotic RIBs, i.e. with increasingly asymmetric proton-to-neutron ratios. In parallel, theoretical approaches have advanced. The extraordinary success of the nuclear shell model has been built upon and extended to account for unexpected phenomena in highly exotic nuclei. Meanwhile, other methodologies rely on the significant progress in Quantum Chromo Dynamics (QCD) to describe nuclear interactions from first principles. These enormous theoretical gains have led to detailed predictions, which this proposal will study. The TITAN mass spectrometers are used to make high-precision measurements to study superallowed beta decay and isospin symmetry. The research program includes investigations of nuclear structure, from the evolution of magic numbers to three-body effects and exotic structures like halos. These precision measurements underpin the nuclear physics required to study nuclear astrophysics and the quest to understand the evolution of chemical elements in the Universe. All scientific inquiries described herein are possible because of the well-established and cutting-edge performance of the TITAN facility in combination with the yield of relevant nuclides in competitive or even unprecedented quantities and quality at ISAC-TRIUMF. Moreover, the fast-approaching era of ARIEL (Advanced Rare IsotopE Laboratory) will triple the available experimental opportunities and provide novel RIBs. Consequently, the world-class and unique TITAN program exploits the extraordinary experimental opportunities for mass measurements and in-trap decay spectroscopy as well as leverages significant investments into the TITAN facility and the associated developments in skills and technology.