Speaker
Description
Direct constraints on P-even/T-odd NN interactions are much weaker than limits on P-odd/T-odd NN interactions. These bounds are so poor that it may complicate the interpretation of future positive EDM signals in nuclei. P-even/T-odd NN interactions can be amplified by factors of ∼10²–10³ at p-wave compound neutron-nucleus resonances. We review two experimental approaches that can take advantage of this amplification: a “zero-crossing’’ method [1], in which a T-odd zero-crossing shift in a forward-backward (n, γ) asymmetry is sought in different resonances combined with final state effect calculations, and a polarized-neutron / tensor-aligned-target forward transmission null test [2,3]. [1] A. L. Barabanov et al., Phys. Rev. Lett. 70, 1216 (1993). [2] V. P. Gudkov, “Nuclear spin dependence of time reversal invariance violating effects in neutron scattering,” Phys. Rev. C 97, 065502 (2018). [3] A. G. Beda and V. R. Skoy, “Current status of research on T invariance in neutron–nuclear reactions,” Phys. Part. Nucl. 38, 1063 (2007).