IRES Track I: Development of the Neutron Optics Parity and Time Violation Experiment in Japan

This IRES Track I proposal will send three cohorts of six U.S. undergraduate students and one U.S. graduate student to Nagoya University, Japan for research and development experiments in conjunction with the existing Japan/US ``Neutron Optics Parity and Time Reversal EXperiment'' (NOPTREX) collaboration. The goal of these experiments is to investigate the physical mechanism responsible for the conversion of antimatter into matter in the early universe.

This is one of the outstanding questions in particle and nuclear physics and cosmology, because the Big Bang theory requires matter and antimatter to have been created in equal parts, although now, we do not observe significant quantities of antimatter in the visible universe.

Five collaborating institutions: University of Kentucky, Indiana University, Berea College, Eastern Kentucky University, and Western Kentucky University will recruit participants from their respective institutions to work together as a student team/cohort. Three of the institutions operate nuclear physics accelerator facilities with neutron sources for student training, and the other two possess outstanding undergraduate physics programs that draw undergraduates from Appalachia.

An innovative aspect of this proposal is that participants will be recruited during the summer prior to the international experience and will receive extensive training with their advisor at their home institution before travelling to Japan. This personalized academic year-long training will prepare the students to make meaningful contributions in a highly technical field and give them extra time to study the Japanese language and culture.

The program will directly train a new generation of talented physicists skilled at working in international collaborations and conducting team-based science. The small scale of the NOPTREX experiment and its use of techniques from many subfields of physics lends itself to hands-on student participation and the development of a broad understanding of physical principles and experimental techniques.

Special consideration will be given to women, Appalachian, first-generation, and underrepresented minorities. Students chosen for the program will enjoy a rich intellectual research experience using the most advanced instrumentation currently available and will gain world-class skills in precision measurements with low-energy neutrons in an international collaborative setting.

As a result, the program will strengthen intellectual and cultural ties between the nuclear science programs of the US and Japan both for the immediate future and in the rising generation of nuclear physicists.

The scientific goal of the NOPTREX collaboration is to conduct a new type of sensitive search for time reversal symmetry violation in polarized neutron transmission through polarized nuclei. The discovery of a new source of time reversal violation in neutron-nucleus interactions would uncover new physics beyond the Standard Model of particle physics and could elucidate the origin of the baryon asymmetry of the Universe.

This experiment exploits special properties of low energy neutron-nucleus resonances, which can act as a natural amplifier of parity and time reversal violation. The design of the experimental apparatus directly embodies and exploits the principle of motion-reversal symmetry to conduct a sensitive search. The Japanese Spallation Neutron Source (JSNS) at the Japan Proton Accelerator Research Complex (J-PARC) is well-suited to host this experiment and will be an ideal backdrop for an international research experience for our students.

Several measurements toward the NOPTREX goals have already been completed both at J-PARC and Los Alamos National Laboratory (LANL).

An innovative aspect of this proposal is the extensive individualized, academic-year training for each student prior to conducting nuclear physics research in Japan. It builds on the highly collaborative work environment centered around both the US multi-institutional team-based R&D experiments at LANL and the international collaborative experiments being performed at J-PARC.

Each US institution contributes specialized hardware expertise and will provide personalized training to IRES participants during the full academic year to prepare them for specific tasks during their research in Japan. Participants will learn collaborative skills and bond as they share their progress with each other and their Japanese mentors in weekly collaboration video conference meetings during the academic year.

Cohort building, scientific training, and cultural awareness will be consolidated during two in-person collaboration/training meetings before travel to Japan.

The students will perform 10 weeks of summer research at Nagoya University under the supervision of Professors Hirohiko Shimizu, Masaaki Kitaguchi, and Takuya Okudaira, with the aid of one US graduate participant. Student research will be integrated in their Fundamental Neutron Physics research group, which is the largest in Japan. Students will test experimental hardware using the low energy neutron test facility at Nagoya University.

They will take a short trip to J-PARC and analyze data collected on the ANNRI beamline at J-PARC. This program is underpinned by our longstanding Japan/US collaborative relationship and our solid record of training students who have worked on the project and conducted NOPTREX research in Japan.

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.