Stepping into the Sea of Instability: The New Sub- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi mathvariant="normal">μ</mml:mi> <mml:mi mathvariant="normal">s</mml:mi> </mml:math> Superheavy Nucleus <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mmultiscripts> <mml:mrow> <mml:mi>Rf</mml:mi> </mml:mrow> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>252</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:mrow> </mml:math>
J. Khuyagbaatar, P. Mošať, J. Ballof, R. A. Cantemir, Ch. E. Düllmann, Katharina Hermainski, F. P. Heßberger, E. Jäger, B. Kindler, J. Krier, N. Kurz, S. Löchner, B. Lommel, Β. Schausten, Yongli Wei, P. Wieczorek, A. Yakushev
Abstract
We report the discovery of the new isotope ^{252}Rf. With its extremely short half-life of 60_{-30}^{+90} ns, it expands the range of half-lives of the known superheavy nuclei by about 2 orders of magnitude. This nucleus was synthesized in its high-K isomeric state, for which we measured a half-life of 13_{-3}^{+4} μs. Our results confirm a smooth onset of decreasing ground-state spontaneous fission half-lives in the neutron-deficient Rf isotopes toward 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.