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تسجيل مستخدم جديدNew Limit on the Permanent Electric Dipole Moment of $^{129}$Xe using $^{3}$He Comagnetometry and SQUID Detection
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We report results of a new technique to measure the electric dipole moment of $^{129}$Xe with $^3$He comagnetometry. Both species are polarized using spin-exchange optical pumping, transferred to a measurement cell, and transported into a magnetically shielded room, where SQUID magnetometers detect free precession in applied electric and magnetic fields. The result from a one week measurement campaign in 2017 and a 2.5 week campaign in 2018, combined with detailed study of systematic effects, is $d_A(^{129}mathrm{Xe}) = (1.4 pm 6.6_mathrm{stat} pm 2.0_mathrm{syst})times10^{-28}~e,mathrm{cm}$. This corresponds to an upper limit of $|d_A(^{129}mathrm{Xe})| < 1.4 times 10^{-27} ~e,mathrm{cm}~(95%~mathrm{CL})$, a factor of five more sensitive than the limit set in 2001.
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We describe a new technique to measure the EDM of $^{129}$Xe with $^3$He comagnetometry. Both species are polarized using spin-exchange optical pumping, transferred to a measurement cell, and transported into a magnetically shielded room, where SQUID
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s obtainable high nuclear polarization and its long spin-coherence time in a homogeneous magnetic field. By measuring the spin precession frequencies of polarized $^{129}$Xe and $^{3}$He, a new upper limit on the $^{129}$Xe atomic EDM $d_mathrm{A}(^{129}mathrm{Xe})$ was reported in Phys. Rev. Lett. 123, 143003 (2019). This writeup proposes a new evaluation method based on global phase fitting (GPF) for analyzing the continuous phase development of the $^{3}$He-$^{129}$Xe comagnetometer signal. The Cramer-Rao Lower Bound on the $^{129}$Xe EDM for the GPF method is theoretically derived and shows the benefit of achieving high statistical sensitivity without bringing new systematic uncertainties. The robustness of the GPF method is verified with Monte-Carlo studies. By optimizing the analysis parameters and adding few more data that could not be analyzed with the former method, a result of [ { d_mathrm{A} (^{129}mathrm{Xe})=(1.1 pm 3.6_mathrm{(stat)} pm 2.0_mathrm{(syst)})times 10 ^{-28} e~mathrm{cm}}, ] is obtained and is used to derive the upper limit of $^{129}$Xe permanent EDM at 95% C.L. [ {|d_text{A}(^{129}text{Xe})| < 8.3 times 10^{-28}~e~mathrm{cm}}. ] This limit is a factor of 1.7 smaller as compared to the previous result.
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