Nuclear Track Emulsion in Search for the Hoyle’s State in Dissociation of Relativistic 12C Nuclei

Study of production of ensembles of alpha-particle triples associated with the Hoyle state (the second excited state 0 + 2 of the 12 C nucleus) in peripheral dissociation of relativistic 12 C nuclei is started. Stacks of pellicles of nuclear track emulsion exposed to 12 C of energy from hundreds MeV to few GeV per nucleon serve as the material of the study. The Hoyle state decays are reconstructed via measurements of emission angles of α-particles with accuracy that allows one to identify the unstable 8 Be nucleus. A role in the Hoyle state of alpha-particle bonds corresponding to 8 Be is determined.