Light nucleus clustering in fragmentation above 1A GeV

An overview of studies of cluster degrees of freedom in light stable and radioactive nuclei with an initial energy above 1A GeV in nuclear emulsions is given. Fragmentation of relativistic nuclei provides an excellent laboratory to explore the transition of nuclei form the ground state to a gas-like phase composed of nucleons and few-nucleon clusters having no excited states, i.e. d, t, 3He, and α. The fragmentation of a large variety of light nuclei was investigated using the emulsions exposed to few AGeV nuclear beams at JINR. Thank to the best spatial resolution and the full solid angle acceptance provided by nuclear emulsions, such an approach allows one to obtain observations reflecting cluster-like features in decays of light nuclear structures. Formation of systems involving the α, d and t nuclei is being studied for a relativistic fragmentation of 6,7Li, 10,11B, 12C, 14N, and 16O nuclei. 3He clustering in 7Be excitation is shown and the next round of tasks, as to whether this kind of nuclear clustering is revealed in heavier neutron-deficient nuclei, might be attacked. (author)