Searches for permanent electric dipole moments (EDMs) in non-degenerate systems are sensitive probes of beyond-standard-model symmetry violation that could explain the dominance of matter over anti-matter. The 225Ra (t1/2=15 d, I=1/2) atom is a particularly attractive system to use for an EDM measurement because its octupole-deformed nucleus, closely spaced ground-state parity doublet, and large nuclear charge make 225Ra uniquely sensitive to symmetry-violating interactions in the nuclear medium. In late 2014, we demonstrated the first “proof-of-principle” measurement of the 225Ra EDM, giving a 95% confidence upper limit of 5×10-22 e-cm. After implementing upgrades to our apparatus, we now observe nuclear spin coherence after 20 s of free evolution – a factor of ten improvement. A new EDM measurement based on the upgraded system improved the 95% confidence upper limit by a factor of 36. Upcoming experimental upgrades have the potential to further improve our EDM sensitivity by many orders of magnitude, allowing us to test symmetry violation at an unprecedented level.
Argonne Physics Division Seminar Schedule