Nuclear, Particle, and Weak Interaction Physics of the Big Bang and Stellar Collapse

University Of California-San Diego, La Jolla CA

Investigators

Abstract

This project probes the fundamental physics of neutrinos and nuclei by exploiting the intersection of exciting new developments in nuclear physics and neutrino physics on the one hand, and the increasingly sophisticated astrophysical and astronomical probes of compact objects, nucleosynthesis histories, and cosmology on the other. A key issue in this enterprise will be studying how neutrinos interact in dense matter and how these interactions may cause neutrinos to change their flavors. To these ends, this UCSD effort will work toward: (1) Formulating and understanding the quantum kinetic equations which govern neutrino flavor evolution in a general medium; (2) Constructing large-scale numerical simulations of neutrino flavor evolution in various supernova, stellar collapse, and compact object merger environments and assessing the feedback of this neutrino flavor physics on the prospects for the synthesis of nuclei in these sites; (3) Understanding neutrino-nucleus interactions, nuclear partition functions, and weak strength distributions in high temperature environments; and (4) Assessing how uncertainties and new beyond-standard-model possibilities in the neutrino sector could impact ideas on nucleosynthesis, dark matter, compact object physics, and cosmology, with an eye toward finding constraints otherwise unobtainable in the laboratory. The research supported in this project will provide insights into how atomic nuclei and radiation behave in extreme conditions of temperature and density. In turn, these insights could give important clues about the nature of some elementary particles and the origin of the elements, for example, in the fiery interiors of supernova explosions, or at the time when the universe was only seconds old. These are fundamental questions that will provide unique opportunities for the training of young scientists, nuclear physicists, at both the graduate and undergraduate levels.