Spectrum of neutrons from the three-particle decay of {sup 6}He(2{sup +}) and its structure

The energy spectrum of neutrons from the {sup 6}He(2{sup +}) {yields} {alpha} + n + n decay is measured in an exclusive experiment. This nucleus is populated in the {sup 7}Li(d,{sup 3}He){sup 6}He* reaction at E{sub d} = 23 MeV. The shape of the neutron spectrum reflects the strong momentum correlations of decay products. The data analysis is carried out using the method of hyperspherical harmonics. It is shown that the observed correlations are manifestations of the specific three-particle effect in the structure of the decaying nucleus. 25 refs., 6 figs., 1 tab.