Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Is Seniority a Partial Dynamic Symmetry in the First $\nu g_{9/2}$
  Shell?   The low-lying structures of the midshell $\nu g_{9/2}$ Ni isotopes $^{72}$Ni
and $^{74}$Ni have been investigated at the RIBF facility in RIKEN within the
EURICA collaboration. Previously unobserved low-lying states were accessed for
the first time following $\beta$ decay of the mother nuclei $^{72}$Co and
$^{74}$Co. As a result, we provide a complete picture in terms of the seniority
scheme up to the first $(8^+)$ levels for both nuclei. The experimental results
are compared to shell-model calculations in order to define to what extent the
seniority quantum number is preserved in the first neutron $g_{9/2}$ shell. We
find that the disappearance of the seniority isomerism in the $(8^+_1)$ states
can be explained by a lowering of the seniority-four $(6^+)$ levels as
predicted years ago. For $^{74}$Ni, the internal de-excitation pattern of the
newly observed $(6^+_2)$ state supports a restoration of the normal seniority
ordering up to spin $J=4$. This property, unexplained by the shell-model
calculations, is in agreement with a dominance of the single-particle spherical
regime near $^{78}$Ni.

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The categories of this paper are: solv-int
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The categories of this paper are: math-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
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The categories of this paper are: gr-qc
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: math
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The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: quant-ph