New Frontiers in Nuclear Astrophysics

Humanity has long been fascinated by the majesty of the night sky. Now, with powerful scientific tools, scientists can better observe stars, galaxies, and the universe itself. Researchers can also better understand the mechanisms behind this majesty. Nuclear physics processes are especially important. Stars are powered by fusion reactions, supernova explosions produce and disperse chemical elements, and the remnants of these explosions accelerate high-energy cosmic rays. A better understanding of these nuclear processes would help us understand the origin, nature, and fate of the universe. A way forward is possible using neutrinos, tiny particles with zero charge, almost no mass, and only weak interactions. Neutrinos are abundantly produced in many astrophysical objects. Detecting neutrinos is very difficult, but doing so can reveal physical conditions deep within these sources, beyond the reach of observations with light. The PI leads a broad program of theoretical work in neutrino astrophysics designed to lead to breakthroughs in understanding astrophysical objects and neutrino properties. Junior scientists will be trained on cutting-edge research as well as career skills. The PI and junior scientists work to share results with the public and to broaden participation by under-represented groups, including the deaf and hard of hearing. The PI’s ambitious research program has three thrusts: solar neutrinos, supernova neutrinos, and high-energy neutrinos. The central tenet of this project is that a broad, integrated program in theoretical neutrino astronomy will powerfully address core questions in nuclear physics while significantly advancing the science of multi-messenger astronomy and beyond the standard model physics. For solar neutrinos, long-term outcomes could include significantly reduced detector backgrounds and thus improvements in the precision of signals from existing detectors, along with facilitating a high-statistics solar-neutrino measurement in the DUNE detector. For supernova neutrinos, these could include better observing a Milky Way supernova and facilitating discovery of the Diffuse Supernova Neutrino Background (DSNB). For high-energy neutrinos, these could include improved probes of atmospheric neutrinos and facilitating discoveries of astrophysical neutrino sources. Individually, the main thrusts of this project could each have a very high impact. Together, they could greatly advance neutrino astronomy, nuclear astrophysics, and more. This project advances the objectives of "Windows on the Universe: the Era of Multi-Messenger Astrophysics", one of the 10 Big Ideas for Future NSF Investments. 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.