The Hoyle State in Relativistic $$^{12}$$C Dissociation

Production of \(\alpha \)-particle triples in the Hoyle state (HS) in dissociation of \({}^{12}\)C nuclei at 3.65 and 0.42 A GeV in nuclear track emulsion is revealed by the invariant mass approach. Contribution of the HS to the dissociation \({}^{12}\)C \(\rightarrow \) 3\(\alpha \) is (11 ± 3)%. Reanalysis of data on coherent dissociation \({}^{16}\)O \(\rightarrow \) 4\(\alpha \) at 3.65 A GeV is revealed the HS contribution of (22 ± 2)%.