Recent results related to excited states of ⁶Be and ¹⁰He

¹ Flerov Laboratory of Nuclear Reactions, JINR, Dubna, 141980, Russia
² Institute of Physics, Silesian University in Opava, Bezrucovo nam. 13, 74601, Czech Republic
³ Bogoliubov Laboratory of Theoretical Physics, JINR, Dubna, 141980, Russia
⁴ GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany
⁵ Russian Research Center “The Kurchatov Institute”, Kurchatov sq. 1, 123182 Moscow, Russia
⁶ Institute of Nuclear Physics PAN, Radzikowskiego 152, PL-31342 Krakow, Poland
⁷ RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
⁸ Fundamental Physics, Chalmers University of Technology, S-41296 Göteborg, Sweden
⁹ All-Russian Research Institute of Experimental Physics, RU-607190 Sarov, Russia

Abstract

The ¹H(⁶Li, ⁶Be)n charge-exchange reaction and the ³H(⁸He,p)¹⁰He two-neutron transfer reaction were recently carried out at the ACCULINNA fragment separator (FLNR, Dubna) to populate the ground and excited states of ⁶Be and ¹⁰He nuclei, respectively. The ⁶Be E_T spectrum (E_T is the ⁶Be energy above its ⁴He+p+p decay threshold) was obtained with high statistics and described by the well-known 0⁺ ground state of ⁶Be at E_T = 1.37 MeV, the 2⁺ state at E_T = 3.05 MeV and a broad structure extending from 4 to 16 MeV which could be interpreted as the isovector soft dipole mode associated with the ⁶Li ground state. In the ¹⁰He case the 0⁺ ground state was found at about 2.1(2) MeV (Γ ~ 2 MeV) above the ⁸He+n+n breakup threshold. Angular correlations observed for 10He decay products show prominent interference patterns allowing to draw conclusions about the structure of low-energy excited states: 1^-(E_T ~ 5 MeV) and 2⁺ (E_T ~ 6 MeV).