Despite its successes, the Standard Model of particle physics cannot be the end of the story. There are too many features that the model does not explain, including the origin of dark matter, why neutrino masses are so light, how the matter-antimatter asymmetry arose, and why Charge-Parity-violation only appears when weak forces are concerned. These are the questions that motivate the Rare Event Search Group at the Massachusetts Institute of Technology (MIT). This award provides support for two beyond-Standard-Model searches: the axion search ABRACADABRA, and the neutrinoless double-beta decay (NLDBD) search KamLAND-Zen and related R&D project NuDot. ABRACADABRA will undertake a search for axions, which are one of the particles postulated to form dark matter. A demonstration of neutrinoless double-beta decay would address the questions of why neutrino masses are so light and what produces the matter-anti-matter asymmetry in the universe.
The program will deliver several beneficial aspects to society through its integration of undergraduates into the program. The multidisciplinary aspects of the projects are appealing to students across a range of majors, exposing students to particle and nuclear physics when they might otherwise have missed the opportunity. The NuDOT and ABRACADABRA detectors are being developed in close association with scientists at local companies. This exposes the undergraduates in the group to alternative career paths as well as promoting strong ties between academia and industry
KamLAND-Zen will be the first ton-scale NLDBD experiment. NuDot, which is a potential upgrade path, can open the door to even large scales. On the other hand, ABRACADABRA is leading the way in a new wave of "table top" beyond-Standard-Model experiments. This is a largely unknown experiment, because it is about to bring out first results. ABRACADABRA brings discovery-level particle physics back to the university. The high intellectual merit of the proposed studies is demonstrated by the excellent alignment of the physics questions with the "science drivers" identified by the Particle Physics Program Prioritization Panel (P5). This proposal addresses: 1) the pursuit of the physics associated with neutrino mass; 2) the identification of the new physics of dark matter; and 3) the exploration of the unknown for new particles, interactions and physical principles. This work is similarly well-aligned with the Long Range Plan of the Nuclear Science Advisory Committee (NSAC), which made the call to move quickly on NLDBD experiments.
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.
