Searching for resonances in the unbound 6Be nucleus by using a radioactive 7Be beam

Knowledge of the 3 He( 3 He,2 p ) 4 He reaction is important for understanding stellar burning and solar neutrino production. Previous measurements have found a surprisingly large rise in the cross section at low energies that could be due to a low-energy resonance in the 3 He + 3 He ( 6 Be) system or electron screening. In the 6 Be nucleus, however, no excited states have been observed above the first 2 + state at E x = 1.67 MeV up to 23 MeV, even though several are expected. The 2 H( 7 Be, 3 H) 6 Be reaction has been studied for the first time to search for resonances in the 6 Be nucleus that may affect our understanding of the 3 He( 3 He,2 p ) 4 He reaction. A 100-MeV radioactive 7 Be beam from the Holifield Radioactive Ion Beam Facility (HRIBF) was used to bombard CD 2 targets, and tritons were detected by using the silicon detector array (SIDAR). A combination of reaction mechanisms appears to be necessary to explain the observed triton energy spectrum.