{Coherent Dissociation $^{12}$C~$\rightarrow$~3$\alpha$ in Lead-Enriched   Emulsion at 4.5 GeV/$c$~per Nucleon
  The transverse-momentum distributions and correlation characteristics of relativistic $\alpha$ particles from the coherent dissociation of a carbon nucleus into three $\alpha$ particles at 4.5 GeV/$c$ are studied in lead-enriched emulsion. Comparative analysis of data obtained in ordinary and lead-enriched emulsion stacks is performed. It is shown that the statistical model of rapid fragmentation does not describe the momentum and correlation characteristics of a $\alpha$ particles in the rest frame of the carbon nucleus. The estimated decay temperature of $^{12}$C is weakly dependent on the target atomic mass. It is shown that the carbon nucleus undergoing fragmentation acquires angular momentum in the collision. 
V. V. Belaga, A. A. Benjaza, V. V. Rusakova, J. A. Salamov and G. M.   Chernov
nucl-ex