High sensitivity of a future search for effects of P -odd/ T -odd interactions on the 0.75 eV p -wave resonance in n⃗</mml:mo…

Neutron transmission experiments can offer a new type of highly sensitive search for time-reversal invariance violating (TRIV) effects in nucleon-nucleon interactions via the same enhancement mechanism observed for large parity violating (PV) effects in neutron-induced compound nuclear processes. In these compound processes, the TRIV cross section is given as the product of the PV cross section, a spin factor κ, and a ratio of TRIV and PV matrix elements. We determined κ to be 0.59±0.05 for 139La+n using both (n,γ) spectroscopy and (→n+139→La) transmission. This result quantifies for the first time the high sensitivity of the 139La 0.75-eV p-wave resonance in a future search for effects of P-odd/T-odd interactions in (→n+139→La) forward transmission.Received 8 December 2023Accepted 7 February 2024DOI:https://doi.org/10.1103/PhysRevC.109.L041602©2024 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasNeutron physicsNucleon induced nuclear reactionsPolarization phenomenaRadiative captureResonance reactionsProperties90 ≤ A ≤ 149ParitySpinT-symmetryTechniquesSpectrometers & spectroscopic techniquesNuclear Physics