Speaker
Description
The observation of a large permanent electric dipole moment (EDM) would represent a clear signal of CP violation from new physics outside the Standard Model. The 199Hg isotope currently provides the most stringent limit on an atomic EDM, which is converted to a limit on the nuclear EDM via a calculation of the Schiff moment, requiring knowledge of the nuclear structure of 199Hg. Ideal information to further develop and constrain the 199Hg Schiff moment nuclear structure theoretical models would be the E3 and E1 strength distributions to the ground state, and E2 transitions amongst excited states. The high level density of 199Hg makes those determinations extremely challenging, however similar information can be obtained from exploring surrounding even-even Hg isotopes. One of the most direct ways of measuring the E3 and E2 matrix elements is through inelastic hadron scattering, and single-nucleon transfer reactions on targets of even-even isotopes of Hg can yield important information on the single-particle nature of 199Hg.
As part of a campaign to study the Hg isotopes, a number of experiments have been performed using the Q3D spectrograph at the Maier-Leibnitz Laboratory, with 22 MeV deuteron beams impinging on enriched Hg32S targets. The first set are inelastic deuteron scattering experiments, 198Hg(d,d')198Hg and 200Hg(d,d')200Hg. Deformation parameters were extracted through coupled-channel calculations with global optical-model potential (OMP) parameter sets for 200Hg. The second set of experiments were single-nucleon transfer reactions, 198Hg(d,p)199Hg and 200Hg(d,t)199Hg, with spin-parity assignments and spectroscopic factors extracted through distorted-wave Born approximation calculations with global OMP sets. Highlights of the results for the four experiments will be presented.
