Splitting Sensitivity of the Ground and 7.6 eV Isomeric States of 229Th

Abstract

The lowest-known excited state in nuclei is the 7.6 eV isomer of 229Th. This energy is within the range of laser-based investigations that could allow accurate measurements of possible temporal variation of this energy splitting. This in turn could probe temporal variation of the fine-structure constant or other parameters in the nuclear Hamiltonian. We investigate the sensitivity of this transition energy to these quantities. We find that the two states are predicted to have identical deformations and thus the same Coulomb energies within the accuracy of the model (viz., within roughly 30 keV). We therefore find no enhanced sensitivity to variation of the fine-structure constant. In the case of the strong interaction the energy splitting is found to have a complicated dependence on several parameters of the interaction, which makes an accurate prediction of sensitivity to temporal changes of fundamental constants problematical. Neither the strong- nor Coulomb-interaction contributions to the energy splitting of this doublet can be constrained within an accuracy better than a few tens of keV, so that only upper limits can be set on the possible sensitivity to temporal variations of the fundamental constants.

arXiv comment4 pages, 2 figures

References in corpus (4)

• Nuclear Ground-State Masses and Deformations
• Enhanced effect of temporal variation of the fine structure constant in diatomic molecules
• Dependence of nuclear binding on hadronic mass variation
• Sensitivity of Nuclear Transition Frequencies to Temporal Variation of the Fine Structure Constant or the Strong Interaction

Cited by in corpus (11)

• Search for New Physics with Atoms and Molecules
• Direct detection of the 229Th nuclear clock transition
• Laser spectroscopic characterization of the nuclear clock isomer ${}^{229m}$Th
• Wigner Crystals of 229Th for Optical Excitation of the Nuclear Isomer
• A proposed experimental method to determine $\alpha$-sensitivity of splitting between ground and 7.6 eV isomeric states in Th-229
• Nuclear clocks based on resonant excitation of gamma-transitions
• On Th229 and time-dependent fundamental constants
• The ${}^{229}$Th isomer: prospects for a nuclear optical clock
• Nuclear charge radii of ${}^{229}$Th from isotope and isomer shifts
• Coulomb energy contribution to the excitation energy in ${}^{229}$Th and enhanced effect of $\alpha$ variation
• On the sensitivity of nuclear clocks to new physics