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arXiv · 2501.08955

Stepping into the Sea of Instability: The New Sub-us Superheavy Nucleus 252Rf

J. Khuyagbaatar·P. Mosat·J. Ballof·R. A. Cantemir·Ch. E. Düllmann·K. Hermainski·F. P. Heßberger·E. Jäger·B. Kindler·J. Krier·N. Kurz·S. Löchner·B. Lommel·B. Schausten·Y. Wei·P. Wieczorek·A. Yakushev
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Abstract

We report the discovery of the new isotope $^{252}$Rf. With its extremely short half-life of $60^{+90}_{-30}$~ns, it expands the range of half-lives of the known superheavy nuclei by about two orders of magnitude. This nucleus was synthesized in its high-$K$ isomeric state, for which we measured a half-life of $13^{+4}_{-3}$~$\mu$s. Our results confirm a smooth onset of decreasing ground-state spontaneous fission half-lives in the neutron-deficient Rf isotopes towards the isotopic border of $10^{-14}$~s, which is the time needed to form an atomic shell. Our findings set a new benchmark for further exploration of phenomena associated with high-$K$ states and inverted fission-stability in the heaviest nuclei.

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J. Khuyagbaatar, P. Mosat, J. Ballof, R. A. Cantemir, Ch. E. Düllmann, K. Hermainski, F. P. Heßberger, E. Jäger, B. Kindler, J. Krier, N. Kurz, S. Löchner, B. Lommel, B. Schausten, Y. Wei, P. Wieczorek, A. Yakushev. 2025-01-15. Stepping into the Sea of Instability: The New Sub-us Superheavy Nucleus 252Rf. https://doi.org/10.1103/physrevlett.134.022501

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