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Studies of pear-shaped nuclei using accelerated radioactive beams

Gaffney, L. P. ; Butler, P. A. ; Scheck, M. ; Hayes, A. B. ; Wenander, F. ; Albers, M. ; Bastin, B. ; Bauer, C. ; Blazhev, A. and Boenig, S. , et al. (2013) In Nature 497(7448). p.199-204
Abstract
There is strong circumstantial evidence that certain heavy, unstable atomic nuclei are 'octupole deformed', that is, distorted into a pear shape. This contrasts with the more prevalent rugby-ball shape of nuclei with reflection-symmetric, quadrupole deformations. The elusive octupole deformed nuclei are of importance for nuclear structure theory, and also in searches for physics beyond the standard model; any measurable electric-dipole moment (a signature of the latter) is expected to be amplified in such nuclei. Here we determine electric octupole transition strengths (a direct measure of octupole correlations) for short-lived isotopes of radon and radium. Coulomb excitation experiments were performed using accelerated beams of heavy,... (More)
There is strong circumstantial evidence that certain heavy, unstable atomic nuclei are 'octupole deformed', that is, distorted into a pear shape. This contrasts with the more prevalent rugby-ball shape of nuclei with reflection-symmetric, quadrupole deformations. The elusive octupole deformed nuclei are of importance for nuclear structure theory, and also in searches for physics beyond the standard model; any measurable electric-dipole moment (a signature of the latter) is expected to be amplified in such nuclei. Here we determine electric octupole transition strengths (a direct measure of octupole correlations) for short-lived isotopes of radon and radium. Coulomb excitation experiments were performed using accelerated beams of heavy, radioactive ions. Our data on Rn-220 and Ra-224 show clear evidence for stronger octupole deformation in the latter. The results enable discrimination between differing theoretical approaches to octupole correlations, and help to constrain suitable candidates for experimental studies of atomic electric-dipole moments that might reveal extensions to the standard model. (Less)
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@article{96d56265-6b53-43cc-823a-e3b2d5f00a05,
  abstract     = {{There is strong circumstantial evidence that certain heavy, unstable atomic nuclei are 'octupole deformed', that is, distorted into a pear shape. This contrasts with the more prevalent rugby-ball shape of nuclei with reflection-symmetric, quadrupole deformations. The elusive octupole deformed nuclei are of importance for nuclear structure theory, and also in searches for physics beyond the standard model; any measurable electric-dipole moment (a signature of the latter) is expected to be amplified in such nuclei. Here we determine electric octupole transition strengths (a direct measure of octupole correlations) for short-lived isotopes of radon and radium. Coulomb excitation experiments were performed using accelerated beams of heavy, radioactive ions. Our data on Rn-220 and Ra-224 show clear evidence for stronger octupole deformation in the latter. The results enable discrimination between differing theoretical approaches to octupole correlations, and help to constrain suitable candidates for experimental studies of atomic electric-dipole moments that might reveal extensions to the standard model.}},
  author       = {{Gaffney, L. P. and Butler, P. A. and Scheck, M. and Hayes, A. B. and Wenander, F. and Albers, M. and Bastin, B. and Bauer, C. and Blazhev, A. and Boenig, S. and Bree, N. and Cederkäll, Joakim and Chupp, T. and Cline, D. and Cocolios, T. E. and Davinson, T. and DeWitte, H. and Diriken, J. and Grahn, T. and Herzan, A. and Huyse, M. and Jenkins, D. G. and Joss, D. T. and Kesteloot, N. and Konki, J. and Kowalczyk, M. and Kroell, Th. and Kwan, E. and Lutter, R. and Moschner, K. and Napiorkowski, P. and Pakarinen, J. and Pfeiffer, M. and Radeck, D. and Reiter, P. and Reynders, K. and Rigby, S. V. and Robledo, L. M. and Rudigier, M. and Sambi, S. and Seidlitz, M. and Siebeck, B. and Stora, T. and Thoele, P. and Van Duppen, P. and Vermeulen, M. J. and von Schmid, M. and Voulot, D. and Warr, N. and Wimmer, K. and Wrzosek-Lipska, K. and Wu, C. Y. and Zielinska, M.}},
  issn         = {{0028-0836}},
  language     = {{eng}},
  number       = {{7448}},
  pages        = {{199--204}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Nature}},
  title        = {{Studies of pear-shaped nuclei using accelerated radioactive beams}},
  url          = {{http://dx.doi.org/10.1038/nature12073}},
  doi          = {{10.1038/nature12073}},
  volume       = {{497}},
  year         = {{2013}},
}