Search for the tri- and tetra-neutron in reactions induced by 11B and 9Be ions on 7Li

In three different heavy ion reactions the energy spectra of the 14O, 15O and 12N nuclei have been measured to obtain some information about their partners in the exit channel - the multineutron systems 4n and 3n. No evidence for the existence of any bound state in the multineutron systems has been obtained at the cross section level of 1 nb/MeV.sr achieved in the experiment. The phase-space analysis has given no positive results concerning the existence of quasistationary states in the 4n and 3n systems either. (orig.)