Fundamental Neutron Physics: Theory and Analysis

Abstract

The goal of the proposal was to study the possibility of searching for manifestations of new physics beyond the Standard model in fundamental neutron physics experiments. This involves detailed theoretical analyses of parity and time reversal invariance violating processes in neutron induced reactions, properties of neutron β-decay, and the precise description of properties of neutron interactions with nuclei. To describe neutron-nuclear interactions, we use both the effective field theory approach and the theory of nuclear reaction with phenomenological nucleon potentials for the systematic description of parity and time reversal violating effects in the consistent way. A major emphasis of our research during the funding period has been the study of parity violation (PV) and time reversal invariance violation (TRIV) in few-body systems. We studied PV effects in non-elastic processes in three nucleon system using both ”DDH-like” and effective field theory (EFT) approaches. The wave functions were obtained by solving three-body Faddeev equations in configuration space for a number of realistic strong potentials. The observed model dependence for the DDH approach indicates intrinsic difficulty in the description of nuclear PV effects and it could be the reason for the observed discrepancies in the nuclear PV data analysis. It shows that themore » DDH approach could be a reasonable approach for analysis of PV effects only if exactly the same strong and weak potentials are used in calculating all PV observables in all nuclei. However, the existing calculations of nuclear PV effects were performed using different potentials; therefore, strictly speaking, one cannot compare the existing results of these calculations among themselves.« less