Projectiles of 11Li were photodisintegrated into 9Li + n + n by absorption of a virtual photon in a Pb target. The momenta of the three particles in the final state were measured, and the dipole strength function was determined up to about 1 MeV above the disintegration threshold. On the average, the 9Li residue had a greater velocity than the neutrons. Interpreted as a post-breakup acceleration of 9Li in the coulomb field of the Pb nucleus, the lifetime of the excited q11Li was found to be too short for the disintegration process to have gone through a resonant state such as the soft dipole resonance. Because the complete kinematics was measured, we could view the events in the rest frame of 11Li. In that frame the distribution of angle between the two neutrons, when the response of the neutron detection system was taken account of, was isotropic. Hence, we have no evidence for a dineutron in 11Li. Two recently-constucted neutron walls will be used in future experiments.
ASJC Scopus subject areas
- Nuclear and High Energy Physics