Prospects of Calibrating the New Physics Sensititivy of Protactinium-229 Via Nuclear Structure Measurements

New sources of charge-parity (CP) violation are thought to be needed to explain the observed absence of visible antimatter in the present day Universe. A non-zero nuclear Schiff moment would be a clear signature of both parity and time-reversal violation and, via the CPT theorem, CP-violation as well. Pear-shaped nuclei such as Ra-225 enhance the observable effect of these symmetry violations by a factor of 1000 or more compared to relatively undeformed nuclei such as Hg-199. Pa-229 is thought to be pear-shaped and has been speculated to have a nearly degenerate parity doublet involving its ground nuclear state. If an excited nuclear state with the same spin but opposite parity as the ground nuclear state in Pa-229 is found to exist with an energy scale of 100 eV, then the sensitivity of Pa-229 to symmetry violations could be 1000 times higher than Ra-225 and 1,000,000 times higher than Hg-199. I will review the current status of the nuclear structure of Pa-229 as weil as our plans to search for the hypothetical nearly degenerate parity doublet of Pa-229 using two complementary techniques. The first technique involves the use of an extreme ultraviolet (EUV) optic coupled to a superconducting tunnel junnel (STJ) sensor to selectively detect the ultra-low energy gammas emitted from the excited nuclear state. The second technique involves the use of an internal conversion electron spectrometer adapted from the design of a spectrometer used to definitely establish the existence of the 8.4 eV state in Th-229. Both techninques require the use of a U-229 beam that will eventually become available at the Facility for Rare Isotope Beams at Michigan State Univeristy.