EnhancedT-odd,P-odd electromagnetic moments in reflection asymmetric nuclei

Abstract

Collective P-and T-odd moments produced by parity and time invariance violating forces in reflection asymmetric nuclei are considered. The enhanced collective Schiff, electric dipole and octupole moments appear due to the mixing of rotational levels of opposite parity. These moments can exceed singleparticle moments by more than two orders of magnitude. The enhancement is due to the collective nature of the intrinsic moments and the small energy separation between members of parity doublets. In turn these nuclear moments induce enhanced T-and P-odd effects in atoms and molecules. First a simple estimate is given and then a detailed theoretical treatment of the collective T-, P-odd electric moments in reflection asymmetric, odd-mass nuclei is presented and various corrections evaluated. Calculations are performed for octupole deformed long-lived odd-mass isotopes of Rn, Fr, Ra, Ac and Pa and the corresponding atoms. Experiments with such atoms may improve substantially the limits on time reversal violation.

Effects of core polarization on the nuclear Schiff moment

“…Second, we have seen that the finite range reduces the mixing matrix elements between the opposite parity states in the case of spherical nuclei. It was argued [7] that the large enhancement factors for the Schiff moments found in quadrupole+octupole nuclei [11] will be reduced when finite range interactions are used.…”

“…223 Fr: This nucleus (Z=87) was found to have an enhanced Schiff moment when the quadrupole+octupole deformations were taken into account [11]. As in the case of 225 Ra for the same reason we computed the single-particle and core polarization values taking 223 Fr to be spherical.…”

“…The heavier isotopes of these elements (A=221-225) are found to have quadrupole plus octupole deformed shapes in the ground states [8,9]. It was suggested that in these heavier isotopes of Rn and Ra (as well as some other elements in this region ) the Schiff moments are strongly enhanced because of the quadrupole+octupole deformations [10,11]. It is therefore useful for the purpose of comparison to calculate accurately the Schiff moments in the neighboring, lighter isotopes where the onset of deformations has not yet occurred.…”

Spectra of barium, radium, and element 120: Application of the combined correlation-potential, singles-doubles, and configuration-interactionab initiomethods

“…Studies of the parity and time-reversal violating atomic electric dipole moment (EDM) and atomic parity violation (APV) are particularly attractive in radium due to orders of magnitude enhancement of the effects, arising from both nuclear and electronic mechanisms: the presence of octupole deformation of the nucleus may lead to several-hundred times nuclear enhancement of the EDM in radium in the electronic ground state compared to mercury (see, e.g., [3,4]), for which the best limit on an atomic EDM has been placed [5]; the presence of anomalously close electronic levels of opposite parity may lead to orders of magnitude electronic enhancement of EDM effects in metastable states and APV effects in certain transitions [6,7].…”

Investigation of the E2 and E3 matrix elements in200Hg using inelastic scattering

“…Recent theories and experiments suggest that some of the light actinides have octupole deformed nuclei [6,7]; the Schiff moment in these systems would be enhanced due to the existence of closelying parity doublet states [8]. Large E3 strengths between states in 199 Hg would also be a signature of enhanced octupole matrix elements.…”