Isovector soft dipole mode in 6Be

A.S. Fomichev, V. Chudoba, I.A. Egorova, S.N. Ershov, M.S. Golovkov, A.V. Gorshkov, V.A. Gorshkov, L.V. Grigorenko, G. Kamiński, S.A. Krupko, I.G. Mukha, Yu.L. Parfenova (+7 others)
2012 Physics Letters B  
By using the 1H(6Li,6Be)n charge-exchange reaction, continuum states in 6Be were populated up to E_t=16 MeV, E_t being the 6Be energy above its three-body decay threshold. In kinematically complete measurements performed by detecting alpha+p+p coincidences, an E_t spectrum of high statistics was obtained, containing approximately ~5x10^6 events. The spectrum provides detailed correlation information about the well-known 0^+ ground state of 6Be at E_t=1.37 MeV and its 2^+ state at E_t=3.05 MeV.
more » ... e at E_t=3.05 MeV. Moreover, a broad structure extending from 4 to 16 MeV was observed. It contains negative parity states populated by Delta L=1 angular momentum transfer without other significant contributions. This structure can be interpreted as a novel phenomenon, i.e. the isovector soft dipole mode associated with the 6Li ground state. The population of this mode in the charge-exchange reaction is a dominant phenomenon for this reaction, being responsible for about 60% of the cross section obtained in the measured energy range.
doi:10.1016/j.physletb.2012.01.004 fatcat:36frwdda4zcehokwbzde4xarci