1. Laser spectroscopy of neutron-rich $^{207,208}$Hg isotopes: Illuminating the kink and odd-even staggering in charge radii across the $N=126$ shell closure
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Goodacre, T. Day, Afanasjev, A. V., Barzakh, A. E., Marsh, B. A., Sels, S., Ring, P., Nakada, H., Andreyev, A. N., Van Duppen, P., Althubiti, N. A., Andel, B., Atanasov, D., Billowes, J., Blaum, K., Cocolios, T. E., Cubiss, J. G., Farooq-Smith, G. J., Fedorov, D. V., Fedosseev, V. N., Flanagan, K. T., Ganey, L. P., Ghys, L., Huyse, M., Kreim, S., Lunney, D., Lynch, K. M., Manea, V., Palenzuela, Y. Martinez, Molkanov, P. L., Rosenbusch, M., Rossel, R. E., Rothe, S., Schweikhard, L., Seliverstov, M. D., Spagnoletti, P., Van Beveren, C., Veinhard, M., Verstraelen, E., Welker, A., Wendt, K., Wienholtz, F., Wolf, R. N., Zadvornaya, A., and Zuber, K.
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Nuclear Experiment ,Nuclear Theory - Abstract
The mean-square charge radii of $^{207,208}$Hg ($Z=80, N=127,128$) have been studied for the first time and those of $^{202,203,206}$Hg ($N=122,123,126$) remeasured by the application of in-source resonance-ionization laser spectroscopy at ISOLDE (CERN). The characteristic \textit{kink} in the charge radii at the $N=126$ neutron shell closure has been revealed, providing the first information on its behavior below the $Z=82$ proton shell closure. A theoretical analysis has been performed within relativistic Hartree-Bogoliubov and non-relativistic Hartree-Fock-Bogoliubov approaches, considering both the new mercury results and existing lead data. Contrary to previous interpretations, it is demonstrated that both the kink at $N=126$ and the odd-even staggering (OES) in its vicinity can be described predominately at the mean-field level, and that pairing does not need to play a crucial role in their origin. A new OES mechanism is suggested, related to the staggering in the occupation of the different neutron orbitals in odd- and even-$A$ nuclei, facilitated by particle-vibration coupling for odd-$A$ nuclei., Comment: 7 pages, 5 figures, Physical Review C, in press
- Published
- 2020
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