New discoveries in basic physics often require scientists to probe Nature at the extremes of energy, distance (very large or very small), intensity, and density, where it is most likely to uncover discrepancies in understanding. Extreme conditions can be produced in the laboratory - the high-energy particle accelerators are an example - but often only after great investments in both scientific personnel and infrastructure. For this reason, over the past two decades physicists interested in fundamental physics have increasingly turned to astrophysics, using the exotic conditions already existing in Nature to test the understanding of the underlying laws of physics. This strategy has proven successful: the high fluxes of neutrinos available from our Sun and cosmic rays led to the discovery of neutrino mass and flavor mixing; studies of the velocities of stars bound in galaxies and galaxy clusters revealed that 85% of the matter in the universe is dark, hidden from us, yet crucial in forming the structures we see in the night sky; observations of the thermonuclear explosions of distant stars led us to conclude that our universe is expanding at an increasing rate, dominated by some mysterious, unidentified vacuum energy; and most recently, a new field of gravitational wave astronomy opened up with Advanced LIGO's detection of the merger of two massive black holes, allowing scientists to test physics in the presence of extreme gravitational fields. This project will bring together nuclear physicists and astrophysicists interested in the quantitative modeling of astrophysical systems, to advance the understanding of the properties of neutrinos, the behavior of nuclear matter at the extremes of temperature and density, and the nature of dark matter.
The main scientific goal of this project is to produce improved models of extreme astrophysical environments, like the cores of supernovae and the interiors of neutron stars, by combining knowledge of the underlying nuclear and neutrino microphysics, with the most advanced tools for numerical simulations in astrophysics. This will enable to reliably connect available astrophysical observables, such as the electromagnetic and nucleosynthetic signals from supernovae, to underlying fundamental microphysics. A second goal is to create the kind of interdisciplinary research environment that will allow the training of a new generation of scientists to work effectively at the interface of astrophysics and fundamental physics. The nuclear physics community will benefit greatly from junior researchers trained in this interdisciplinary science, who can then bridge the gap between astrophysical and astronomical measurements on one hand, and their interpretation in terms of our "standard model" of fundamental interactions, and its possible extensions, on the other.
