New isotope <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Ds</mml:mi><mml:mprescripts/><mml:none/><mml:mn>276</mml:mn></mml:mmultiscripts></mml:math> and its decay products <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Hs</mml:mi><mml:mprescripts/><mml:none/><mml:mn>272</mml:mn></mml:mmultiscripts></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Sg</mml:mi><mml:mprescripts/><mml:none/><mml:mn>268</mml:mn></mml:mmultiscripts></mml:math> from the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi>Th</mml:mi><mml:mprescripts/><mml:none/><mml:mn>232</mml:mn></mml:mmultiscripts><mml:mo>+</mml:mo><mml:mmultiscripts><mml:mi>Ca</mml:mi><mml:mprescripts/><mml:none/><mml:mn>48</mml:mn></mml:mmultiscripts></mml:mrow></mml:math> reaction
Yu. Ts. Oganessian, V. K. Utyonkov, M. V. Shumeiko, F. Sh. Abdullin, S. N. Dmitriev, D. Ibadullayev, М. Г. Иткис, N. D. Kovrizhnykh, D. A. Kuznetsov, O. V. Petrushkin, A. V. Podshibiakin, А. N. Polyakov, A. G. Popeko, I. S. Rogov, R. N. Sagaidak, L. Schlattauer, V. D. Shubin, D. I. Solovyev, Yu. S. Tsyganov, A. A. Voinov, V. G. Subbotin, Н. С. Бубликова, M. G. Voronyuk, A. V. Sabelnikov, A. Yu. Bodrov, Z. G. Gan, Z. Y. Zhang, M. H. Huang, H. B. Yang
Abstract
The $^{232}\mathrm{Th}+^{48}\mathrm{Ca}$ reaction has been studied at the gas-filled separator DGFRS-2 online to the cyclotron DC280 at the SHE Factory at JINR. Three new nuclides were synthesized for the first time: a spontaneously fissioning (SF) $^{268}\mathrm{Sg}$ with the half-life ${T}_{\mathrm{SF}}=13\begin{array}{c}+17\\ \ensuremath{-}4\end{array}$ s; an \ensuremath{\alpha} decaying $^{272}\mathrm{Hs}$ with ${T}_{\ensuremath{\alpha}}=0.16\begin{array}{c}+0.19\\ \ensuremath{-}0.06\end{array}$ s and ${E}_{\ensuremath{\alpha}}=9.63\ifmmode\pm\else\textpm\fi{}0.02\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}$; and $^{276}\mathrm{Ds}$ with ${T}_{1/2}=0.15\begin{array}{c}+0.10\\ \ensuremath{-}0.04\end{array}$ ms, ${E}_{\ensuremath{\alpha}}=10.75\ifmmode\pm\else\textpm\fi{}0.03\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}$, and an SF branch of 57%. The decay properties of these nuclei are in agreement with the systematics of experimental partial half-lives and \ensuremath{\alpha}-decay energies of heavy known nuclei, as well as spontaneous-fission half-lives. The cross sections of the $4n$-evaporation channel of $0.07\begin{array}{c}+0.17\\ \ensuremath{-}0.06\end{array}$ pb, $0.7\begin{array}{c}+1.1\\ \ensuremath{-}0.5\end{array}$ pb, and $0.11\begin{array}{c}+0.46\\ \ensuremath{-}0.09\end{array}$ pb were measured at 231, 238, and 251 MeV, respectively.