Evidence for a New Low-Lying Resonance State in [Formula presented]

Abstract

Low-lying resonance states in [Formula presented], formed after fragmentation reactions of a 227 MeV/nucleon [Formula presented] beam on a carbon target, have been studied. Coincidences between [Formula presented] nuclei and neutrons, corresponding to the one-neutron knockout channel in [Formula presented], were selected. The relative energy spectrum in the [Formula presented] system shows a structure, which is interpreted as the [Formula presented] ([Formula presented]) ground state, unbound with 0.43(2) MeV relative to the [Formula presented] system and a width of [Formula presented] overlapping with an excited ([Formula presented]) state observed at 1.0(1) MeV with a width of [Formula presented]. © 2002 The American Physical Society.