The ⁸He and ¹⁰He spectra studied in the (t

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• 作者：M.S. Golovkov ; L.V. Grigorenko ; G.M. Ter-Akopian ; A.S. Fomichev ; Yu.Ts. Oganessian ; V.A. Gorshkov ; S.A. Krupko ; A.M. Rodin ; S.I. Sidorchuk ; R.S. Slepnev ; S.V. Stepantsov ; R. Wolski ; D.Y. Pang ; V. Chud
• 关键词：⁶He ; ⁸He beams ; Tritium gas target ; Resonance states ; Hyperspherical harmonic method ; Soft dipole mode ; Neutron halo
• 刊名：Physics Letters B
• 出版年：2009
• 出版时间：9 February 2009
• 年：2009
• 卷：672
• 期：1
• 页码：22-29
• 全文大小：681 K

文摘

The low-lying spectra of ⁸He and ¹⁰He nuclei were studied in the ³H(⁶He, p)⁸He and ³H(⁸He, p)¹⁰He transfer reactions. The 0⁺ ground state (g.s.) of ⁸He and excited states, 2⁺ at 3.6–3.9 MeV and (1⁺) at 5.3–5.5 MeV, were populated with cross sections of 200, 100–250, and 90–125 μb/sr, respectively. Some evidence for a ⁸He state at about 7.5 MeV was obtained. We discuss a possible nature of the near-threshold anomaly above 2.14 MeV in ⁸He and relate it to the population of a 1⁻ continuum (soft dipole excitation) with a peak value at about 3 MeV. The lowest energy group of events in the ¹⁰He spectrum was observed at 3 MeV with a cross section of 140 μb/sr. We argue that this result is consistent with the previously reported observation of ¹⁰He providing the new ¹⁰He g.s. position at about 3 MeV.