Fragmentation of carbon into three alphas in propane bubble chamber at 4.2 GeV/c

A search for the reaction of coherent dissociation 12C→3α on carbon nuclei at 4.2 GeV/c per nucleon has been made. The cross section of this reaction and it's dependence on the mass number of nucleus were evaluated. The comparative analysis of the momentum and correlation characteristics of secondary alpha-particles in the laboratory and centre -of mass frames of fragmentating nucleus with the incoherent events and with the same data for heavy targets was fulfilled. It was shown that the mechanism of the 12C → 3α decay is essentially changed with the increasing of the mass number of target nucleus and depends on the character of nucleus-nucleus interaction. (author). 18 refs., 6 figs., 3 tabs