Parity Violation in the 3.2 eV p-wave Neutron Resonance in $^{131}$Xe*

Time reversal (TR) violation in polarized neutron transmission through polarized nuclei can be used to search for beyond the Standard Model physics. A few heavy nuclei including $^{139}$La, $^{81}$Br, and $^{131}$Xe can amplify both parity-odd and parity-odd/time-reversal odd effects due to their mixing of s-wave and p-wave resonances[1]. We focus on $^{131}$Xe, where a previous experiment observed a large P-odd asymmetry in the 3.2eV p-wave resonance of $^{131}$Xe[1,2]. We present the design for a cryogenic, solid Xe target to be used in a remeasurement of the P-odd asymmetry on the 3.2 eV resonance to higher precision. We will use a polarized 3He neutron spin filter to polarize the 3.2 eV neutrons. It has also been shown that $^{131}$Xe is polarizable using spin exchange optical pumping techniques[1,3], which will be important for future tests measuring TR asymmetry. [1] J.J. Szymanski, W. M. Snow, et al., Phys. Rev. C{\bf 53}, R2576 (1996). [2] A. Komives, J. D. Bowman, et al., {\it Resonance parameters and analyzing powers of neutron resonances in natural Xenon}, unpublished (1999). [3] Stupic KF, Cleveland ZI, Pavlovskaya GE, Meersmann T, {\it Hyperpolarized $^{131}$Xe NMR spectroscopy}, Nucl. Phys. {\bf A401}, Journal of Magnetic Resonance. {\bf 208}: 58–69 (2011).