Unstable nuclei in coherent dissociation of relativistic nuclei 7,9Be, 10B and 10,11C

Abstract

Contribution of the unstable nuclei 7Be, 8Be and ®B into coherent dissociation events ("white" stars) of relativistic nuclei 7,9Be, 10B and 10,11C is under study on the basis of a nuclear track emulsion exposed to beams of the JINR Nuclotron. Distributions over the opening angle of α-pairs indicate to a simultaneous presence of virtual 8Beg.s. and 8Be2+ states in the ground states of the 9Be and 10C nuclei. The core 9B is manifested in the 10C nucleus with a probability of (30 ± 4)%, Selection of the 10C "white" stars accompanied by 8Beg.s. (9B) leads to the appearance in the excitation energy distribution of 2α2p "quartets" of the distinct peak with a maximum at 4.1 ± 0.3 MeV. 8Beg.s. decays are presented in 21% 2He + 2H and 19% in the 3He of the all 11C "white" stars. 9Bg.s. decays are identified in "white" stars 11C → 2He + 2H constituting 14% of the 11C "white" stars. The 9B nucleus. is manifested in the "white" stars 10B → 2He + 2H with a probability of (9 ± 1)%. For the 10B case yield of 8Beg.s. nuclei with the respect to 9B is about a factor of 3 higher than 9B.