CAREER: Uncertainty Estimates in Low-Energy Nuclear Physics

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Many important reactions in nuclear physics cannot be measured with currently available experimental techniques. For example, the reaction probability of the process in which two protons fuse to a Deuteron (a bound state of a neutron and a proton) is an important process in the sun. However, it cannot be measured experimentally and only theoretical calculations can provide this rate. In the absence of guidance from experiment, it becomes important to quantify theoretical uncertainties. To address these issues, this project will use analytical and numerical methods to calculate reaction rates for astrophysically relevant reaction rates and new parametrizations of the internuclear interaction that will be useful to the larger nuclear physics community. Specifically, the PI and his students will use nuclear interactions constructed using effective field theory. In this theoretical approach, the nuclear interaction model can be systematically improved to improve the accuracy of the calculation. Intrinsic error of this approach will be determined using numerical techniques. This project will allow not only for a better understanding of important nuclear processes occurring in the universe, but also the project will provide a stimulating training ground for students and postdoctoral fellows and outreach community activities.This project aims at improving our understanding of electroweak processes using effective field theory. A number of weak processes in few-nucleon systems will be calculated within the unified framework of 'pionless' effective field theory. Specifically, the well-measured decay half-life time of tritium will be studied theoretically in order to obtain a highly accurate description for proton-proton fusion and weak proton capture on Helium-3. Furthermore, the PI and his student will study the intrinsic error of Hamiltonians and associated electroweak currents generated in 'pionfull' effective field theory. The PI will use novel techniques to analyze uncertainties in matrix elements calculated with the chiral potential and the associated electroweak currents in order to account correctly for the intrinsic error of the Hamiltonian order-by-order. With his collaborators, the PI will then use these results to calculate observables such as half-life times or total decay rates that are currently measured to new accuracy and with correct error estimates. The resulting interactions and currents will be made available to the nuclear theory community.