Search for time reversal invariance violation in neutron transmission

Time reversal invariance violating (TRIV) effects in neutron transmission through a nuclear target are discussed. We demonstrate the existence of a class of experiments that are free from false asymmetries. We discuss the enhancement of TRIV effects for neutron energies corresponding to $p$-wave resonances in the compound nuclear system. We analyze a model experiment and show that such tests can have a discovery potential of ${10}^2–{10}^4$ compared to current limits.

Figure 1

Apparatus to search for time reversal symmetry violation. The collimators, polarizer/analyzer, and polarized target are mounted on a turntable that rotates about a vertical axis. In the forward configuration, the neutrons first pass through the polarizer/analyzer, then through the target, and then are detected. In the reversed configuration the neutrons pass through the polarized target, then through the polarizer/analyzer, and then are detected. The dashed line is the horizontal axis of symmetry of the apparatus. The solid line is a neutron trajectory. The collimators select the same bundles of trajectories in the two configurations. The signs of the magnetic fields, the target polarization, and the polarizer/analyzer direction are all opposite in the two configurations.

Figure 2

Pseudomagnetic field in lanthanum aluminate crystals.

Figure 3

The dependence of neutron EDM (solid line), ${}^3\text{He}$ EDM (dot-dashed line), ${}^3\text{H}$ EDM (dotted line), and parameter $\lambda$ on TRIV $\pi$ mesons isoscalar and isotensor coupling constants.

Figure 4

The dependence of neutron EDM (solid line), ${}^3\text{He}$ EDM (do-dashed line), ${}^3\text{H}$ EDM (dotted line), and parameter $\lambda$ on TRIV $\pi$ mesons isoscalar and isovector coupling constants,