Search for resonances in the three- and four-neutron systems in the 7Li(7Li, 11C)3n and 7Li( 7Li, 10C)4n Reactions

Abstract

The spectra of the 11C and 10C nuclei from the 7Li(7Li, 11C)3n and 7Li( 7Li, 10C)4n reactions, respectively, have been measured at a 7Li energy of 82 MeV and an angle of 2° up to excitation energies of 20-30 MeV of the desired multineutrons. The experiments were carried out with a magnetic separator, which made it possible to significantly increase the intensity of a beam by removing scattered particles and to carry out small-angle measurements. The energy spectra are well described by four- and five-particle phase spaces. No evidence has been found for the existence of nuclear stable and resonance states (with Γ < 3 MeV) of multineutrons. The upper limits have been obtained for the cross sections for the formation of nuclear stable states of 3n (1.4 nb/sr) and 4n (0.1 nb/sr) in the center-of-mass system. © 2005 Pleiades Publishing, Inc.