Study of the Involvement of 8 Be and 9 B Nuclei in the Dissociation of Relativistic 10 C, 10 B, and 12 C Nuclei

The results obtained by estimating the contribution of 8Be and 9B nuclei to the coherent dissociation of 10 C, 10 B, and 12 C relativistic nuclei in nuclear track emulsions (“white” stars) are presented. The selection of white stars accompanied by 9B leads to a distinct peak appearing in the distribution of the excitation energy of 2α2 p ensembles and having a maximum at 4.1 ± 0.3 MeV. A 8Be nucleus manifests itself in the coherent-dissociation reaction 10 B → 2 He + H with a probability of (25 ± 5)%, (14 ± 3)% of it being due to 9B decays. The ratio of the branching fractions of the 9 B + n and 9 Be + p mirror channels is estimated at 6 ± 1. An analysis of the relativistic dissociation of 12 C nuclei in a nuclear track emulsion revealed nine 3α events corresponding to the Hoyle state.