A New Search for the Atomic EDM of $^{129}$Xe at FRM-II (Munich Research Reactor)

Electric dipole moments (EDMs) arise due to the breaking of time-reversal or, equivalently, $CP$-symmetry. Although all searches have so far only set upper limits on EDMs, the motivation for more sensitive searches is stronger than ever. The present limit of $6\times 10^{-27}$ $e*$cm (95\% CL) for the $^{129}$Xe EDM helps constrain $CP$-violating parameters within nuclei. A new effort at FRM-II incorporating a $^3$He comagnetometer can potentially improve this limit by over three orders of magnitude. The noble gas mixture is polarized by spin-exchange optical pumping and then transferred into a high-performance magnetically shielded room. A SQUID magnetometer array measures the precession frequencies in the presence of applied electric- \& magnetic-fields. Recent test runs indicate that the experiment is capable of an EDM sensitivity of $10^{-28}$ $e*$cm in one day.