Preponderance of triaxial shapes in atomic nuclei predicted by the proxy-SU(3) symmetry

Fuente: arXiv
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Main Authors: Bonatsos, Dennis, Martinou, Andriana, Peroulis, S. K., Petrellis, D., Vasileiou, P., Mertzimekis, T. J., Minkov, N.
Format: Preprint
Published: 2024
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_version_ 1866909622770597888
author Bonatsos, Dennis
Martinou, Andriana
Peroulis, S. K.
Petrellis, D.
Vasileiou, P.
Mertzimekis, T. J.
Minkov, N.
author_facet Bonatsos, Dennis
Martinou, Andriana
Peroulis, S. K.
Petrellis, D.
Vasileiou, P.
Mertzimekis, T. J.
Minkov, N.
contents The proxy-SU(3) symmetry predicts, in a parameter-free way, based only on the Pauli principle and the short-range nature of the nucleon-nucleon interaction, non-vanishing values of the collective variable gamma almost everywhere across the nuclear chart. Substantial triaxiality with gamma between 15 and 45 degrees is proved to be expected along horizontal and vertical stripes on the nuclear chart, covering the nucleon numbers 22-26, 34-48, 74-80, 116-124, 172-182. Empirical support for these stripes is found by collecting all even-even nuclei for which the first two excited 2+ states are known, along with the B(E2)s connecting them, as well as the second 2+ state to the ground state. The stripes are related to regions in which oblate SU(3) irreducible representations appear, bearing similarity to the appearance of triaxiality within the SU(3)* dynamical symmetry of the interacting boson model-2. Detailed comparisons of the proxy-SU(3) predictions to the data and to predictions by state-of-the-art Monte Carlo shell model calculations for deformed N=94, 96, 98 isotones in the rare earth region show good overall agreement, with the exception of Z=70 and N=94, which correspond to fully symmetric proxy-SU(3) irreps, suggesting that the latter are an artifact of the method which can be amended by considering the influence of the neighboring irreps.
format Preprint
id arxiv_https___arxiv_org_abs_2411_12281
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Preponderance of triaxial shapes in atomic nuclei predicted by the proxy-SU(3) symmetry
Bonatsos, Dennis
Martinou, Andriana
Peroulis, S. K.
Petrellis, D.
Vasileiou, P.
Mertzimekis, T. J.
Minkov, N.
Nuclear Theory
The proxy-SU(3) symmetry predicts, in a parameter-free way, based only on the Pauli principle and the short-range nature of the nucleon-nucleon interaction, non-vanishing values of the collective variable gamma almost everywhere across the nuclear chart. Substantial triaxiality with gamma between 15 and 45 degrees is proved to be expected along horizontal and vertical stripes on the nuclear chart, covering the nucleon numbers 22-26, 34-48, 74-80, 116-124, 172-182. Empirical support for these stripes is found by collecting all even-even nuclei for which the first two excited 2+ states are known, along with the B(E2)s connecting them, as well as the second 2+ state to the ground state. The stripes are related to regions in which oblate SU(3) irreducible representations appear, bearing similarity to the appearance of triaxiality within the SU(3)* dynamical symmetry of the interacting boson model-2. Detailed comparisons of the proxy-SU(3) predictions to the data and to predictions by state-of-the-art Monte Carlo shell model calculations for deformed N=94, 96, 98 isotones in the rare earth region show good overall agreement, with the exception of Z=70 and N=94, which correspond to fully symmetric proxy-SU(3) irreps, suggesting that the latter are an artifact of the method which can be amended by considering the influence of the neighboring irreps.
title Preponderance of triaxial shapes in atomic nuclei predicted by the proxy-SU(3) symmetry
topic Nuclear Theory
url https://arxiv.org/abs/2411.12281