Grant: Subatomic Physics Envelope - Project

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.