NOPTREX: A Search for Time-Reversal Invariance Violation in Polarized Neutron-Nuclear Resonance Interactions

One of the motivations to search for new physics Beyond the Standard Model (BSM) is to understand the baryon asymmetry present in the Universe, namely the discrepancy between the theoretical prediction of the baryon asymmetry based on the SM and the value obtained through observations of the cosmic microwave background. The Neutron OPtics Time Reversal EXperiment (NOPTREX) Collaboration seeks to measure signatures of parity-odd (P-odd) and time-reversal-symmetry-odd (T-odd) interactions in polarized neutron transmission through polarized nuclear targets which contain p-wave resonances in the eV energy range. This can be done through the use of neutron transmission resonance spectroscopy. The relative strength of the weak and strong coupling constants is known to be ~10^-7; however, the many-body nature of a resonant compound nuclear system results in amplification effects specific to the weak interaction which can increase the discovery potential for such a measurement by a factor of 10⁵-10⁶, making this an attractive system in which to study T-violation. This talk will outline the status of our work on the neutron-nucleus resonance spectroscopy techniques needed to quantify the sensitivity which can be attained through this approach.