First Measurement of Neutron Birefringence in Polarized ${}^{129}$Xe and ${}^{131}$Xe Nuclei

Abstract

We present the first measurements of polarized neutron birefringence in transmission through nuclear-polarized ${}^{129}$Xe and ${}^{131}$Xe gas and determine the neutron incoherent scattering lengths $b_i{(}^{129}Xe)=0.186\pm (0.021{)}_{stat.}\pm (0.004{)}_{syst.}\text{ fm}$ and $b_i{(}^{131}Xe)=2.09\pm (0.29{)}_{stat.}\pm (0.12{)}_{syst.}\text{ fm}$ for the first time. These results determine the essential parameter needed for interpretation of spin-dependent neutron-scattering studies on polarized xenon ensembles, with possible future applications ranging from tests of time-reversal violation to mode-entangled neutron scattering experiments on nuclear-polarized systems.

7 pages, 3 figures, submitted to PRL