Spin dependence in the p-wave resonance of y139La+nt

We measured the spin -dependent cross section at a neutron -induced p -wave resonance using a polarized epithermal neutron beam and a polarized nuclear target. Our study focuses on the 0.75 eV p -wave resonance of 139La +n , where previous experiments have shown a large enhancement of parity violation. The spin dependence of the neutron absorption cross section of polarized 139La and polarized neutrons determines the partial neutron width of the p -wave resonance. This partial width is a key parameter needed to determine the sensitivity of this system to possible parity -odd and time reversal -odd interactions beyond the standard model. Our findings therefore serve as a foundation for a future search for time reversal violation in this compound nuclear system.