Nuclear Experimental Probes of Neutrino Mass

Indiana University, Bloomington IN

Investigators

Abstract

Much remains to be learned about neutrinos despite their great abundance in the universe. Chief among their unknown properties is their mass - a quantity that is relevant to physics at all scales: from the formation of the structure of the cosmos down to the minutest particle nature. Two parallel lines of investigation related to this question are pursued with this award. In the first, a precise measurement the highest-energy decay electrons of tritium beta decay can infer the neutrino mass with no model dependence or theoretical uncertainty. In the second line of investigation, the nature of neutrinos and whether they might uniquely be their own antiparticles will be probed by searching for neutrinoless double beta decay (0νββ). Both experiments are pushing the frontiers of detector technology to achieve their science goals, and graduate students will be supported and trained in these techniques. Additionally, this award will support outreach as the Great American Eclipse of 2024 passes through Bloomington, IN. A next-generation concept for a tritium endpoint neutrino mass experiment is being pursued with Project 8 using the novel Cyclotron Radiation Emission Spectroscopy (CRES) technique. During the award period, work will focus on scalability of CRES towards the required multi-m^3-scale for the ultimate experiment. The research team will lead the experimental controls systems of new demonstrator apparatuses, as well as contribute to other aspects of the project. In 0νββ, this award supports work on the 76Ge experiments, Majorana Demonstrator and LEGEND. Final science results of Majorana are expected early in the award period, with LEGEND-200 commissioning concurrently. The research team will focus on pulse shape analysis towards improved characterization and rejection of backgrounds. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.