New Frontiers in Nuclear Astrophysics

Ohio State University, The, Columbus OH

Investigators

Abstract

The visible universe is shaped by nuclear physics processes: stars are powered by fusion reactions, supernova explosions produce and disperse chemical elements, and the remnants of these explosions accelerate cosmic rays. A better understanding of these processes will help us understand the origin, nature, and fate of the universe. A new way forward is possible using neutrinos, tiny particles with zero charge, almost no mass, and only weak interactions. Neutrinos are abundantly produced in astrophysical systems. Detecting neutrinos is extraordinarily difficult, but, when successful, it reveals physical conditions of sources that are otherwise hidden by thick layers of matter that neutrinos can readily stream through. The PI will lead a broad program of theoretical work on neutrino astrophysics, closely coupled to experimental physics and observational astronomy, designed to lead to breakthroughs in understanding astrophysical systems and neutrino properties. Junior scientists will be trained on cutting-edge research as well as the general skills needed for career success. The PI and junior scientists will work to share results with the public and to broaden participation by under-represented groups, including the Deaf and Hard of Hearing. The PI will lead a research program with four thrusts: solar neutrinos, supernova burst neutrinos, the Diffuse Supernova Neutrino Background (DSNB), and the particle properties of neutrinos. These thrusts are closely connected. Eventual outcomes could include sensitive new tests of solar-neutrino mixing and first detections of certain solar-fusion processes; precise observation of a Milky Way supernova and detailed probes of the hot proto-neutron star and possible black hole formation; and unprecedented new tests of neutrino properties plus the discovery of new neutrino sources. An especially important goal is the detection and interpretation of the DSNB, the cosmic flux of neutrinos and antineutrinos produced by the core collapses of massive stars over billions of years. The latter is now within reach because Super-Kamiokande has accepted the Beacom-Vagins GADZOOKS! proposal to add gadolinium to enable neutron detection. Detection of these neutrinos will probe the cosmic star formation history that shapes the visible universe and builds up chemical elements, neutron stars and black holes, and cosmic rays. It would also probe the neutrino emission per core collapse that reflects the physics of neutron stars and black holes, and allows new tests of neutrino properties. This project is co-funded by the Division of Physics and the Division of Astronomical Sciences in the Directorate of Mathematical & Physical Sciences.