Measurement of parity-nonconserving rotation of neutron spin in the 0.734-eV p-wave resonance of ${}^{139}La$

Abstract

The parity nonconserving spin rotation of neutrons in the 0.734-eV p-wave resonance of ${}^{139}La$ was measured with the neutron transmission method. Two optically polarized ${}^{3}He$ cells were used before and behind a a 5-cm long ${}^{139}La$ target as a polarizer and an analyzer of neutron spin. The rotation angle was carefully measured by flipping the direction of ${}^{3}He$ polarization in the polarizer in sequence. The peak-to-peak value of the spin rotation was found to be $(7.4\pm 1.1)\times 10^{-3}$ rad/cm which was consistent with the previous experiments. But the result was statisticallly improved. The s-p mixing model gives the weak matrix element as $xW=(1.71\pm 0.25)$ meV. The value agrees well with the one deduced from the parity-nonconserving longitudinal asymmetry in the same resonance.

References in corpus (2)

• Parity Violation in Proton-Proton Scattering
• A measurement of the absolute neutron beam polarization produced by an optically-pumped 3He spin filter

Cited by in corpus (2)

• Optically Polarized ${}^3$He
• Time-Reversal Violation in Threshold $\vec{n}$ $\vec{p}$ Scattering