Neutron correlations in the decay of the first excited state of 11Li

The decay of unbound excited Li-11 was measured after being populated by a two-proton removal from a B-13 beam at 71 MeV/nucleon. Decay energy spectra and Jacobi plots were obtained from measurements of the momentum vectors of the Li-9 fragment and neutrons. A resonance at an excitation energy of similar to 1.2 MeV was observed. The kinematics of the decay are equally well fit by a simple dineutron-like model or a phase-space model that includes final state interactions. A sequential decay model can be excluded. (C) 2016 Elsevier B.V. All rights reserved.