Calculations of time-reversal-symmetry-violation sensitivity parameters based on analytic relativistic coupled-cluster gradient theory

Electric dipole moments and the search for new physics

“…Two basic approaches have been taken so far: the nuclear shell model [99] and nuclear density functional theory (DFT) [100]. The first method, which requires that the nucleus be not too strongly deformed, has been applied several times to the Schiff moment of 1 99Hg, most recently in Yanase and Shimizu [101], and the second has been applied both to that isotope and light actinides such as 225 Ra [102,103]. The results exhibit fairly large discrepancies, pointing to a problem with these phenomenological approaches: there is no way to reliably estimate uncertainty.…”

“…One version of the IMSRG, the In-Medium Generator Coordinate Method (IM-GCM), builds the reference state from a deformed mean-field state, projected onto good angular momentum. The sophisticated reference state makes the method particularly able to describe collective properties such as E2 transitions [110] and will be useful in computing the enhanced Schiff moments of octupole-deformed nuclei such as 225 Ra. Another variant, the valence-space IMSRG, uses valence single-particle spaces to construct reference ensembles, leading to shell-model-like calculations with rigorously derived effective operators.…”

“…For spherical nuclei, the MQM is roughly independent of Z, while for quadrupole-deformed nuclei there is a collective enhancement [216][217][218] which scales roughly as M ∝ Z 2/3 . The structure-dependent factors q require detailed calculations of electron or nuclear wavefunctions in order to evaluate [195,[219][220][221][222][223][224][225][226][227][228][229][230][231][232][233][234][235]. For electrons in atoms/ions, q at is largest for systems where s and p orbitals are the main components of the states mixed by the external (for atoms) or internal (for ions in a molecule) E-field.…”

“…New experiments with atoms, primarily sensitive to underlying hadronic CPV, are also underway. A particularly promising approach is to take advantage of the large structural enhancement of the NSM in the octupole-deformed nuclei 225 Ra or 223 Ra (Z = 88) [102,241,252,269,270]. Here, the Ra atoms are laser-cooled and optically trapped, then subjected to potentially very large electric fields.…”

Rotating and vibrating symmetric top molecule RaOCH$_3$ in the fundamental $\mathcal{P}$, $\mathcal{T}$-violation searches

“…The possibility to search for the Schiff moment on the 225 RaOCH + 3 ion was studied in [41]. The values of E eff for a number of the MOCH 3 molecules (including RaOCH 3 ) were obtained for the fixed equilibrium configuration in [42].…”