Limit on the nuclear Schiff moment of europium-153

Abstract

The Schiff moment of a nucleus is a symmetry-violating nuclear moment that indicates new physics beyond the Standard Model. We place the limit, $|\mathcal{S}({}^{153}$Eu)$|<1.7\times 10^{-8}$ $e$fm${}^3$ (95\% confidence), on the Schiff moment of the ${}^{153}$Eu nucleus, using nuclear spin resonances in two ensembles of oppositely-polarized ${}^{153}$Eu${}^{3+}$ ions in a Y${}_2$SiO${}_5$ crystal. This measurement using octupolar nuclei in a mm-scale crystal constrains new physics at the TeV energy-scale.