AB INITIO · Stellar Astrophysics and an Ab Initio Description of Thermonuclear Reactions

Light-ion fusion reactions in thermal plasmas determine the course of stellar evolution. Nuclear reactions such as 7Be(p,gamma)8B, which is responsible for most of our knowledge of neutrino oscillations, the 3He(alpha,gamma)7Be identified as the most important reaction limiting the accuracy of the standard solar model, the triple-alpha fusion to form 12C and the famous 12C(alpha,gamma)16O reaction are still not known with anywhere near the required precision. Their experimental measurement at low energies relevant for astrophysics processes is very difficult or even impossible. Remarkably, no fundamental theory for these nuclear reactions exists today. It is the goal of this proposal to develop an entirely new ab initio formalism with a predictive power applicable to nuclear reactions important for astrophysics. A fundamental theory for light-ion fusion reactions presents a substantial challenge, as detailed nuclear structure information for the entire system is required. The proposed approach is based on the ab initio no-core shell model (NCSM), which is a well established theoretical framework presently capable to describe nuclear structure from inter-nucleon forces derived by means of effective field theory from quantum chromodynamics. Its extension to the description of nuclear reactions will be achieved by adopting and adapting the resonating group method technique.