Exploring Neutron-Rich Oxygen Isotopes with MoNA

The Modular Neutron Array (MoNA) was used in conjunction with a large-gap dipole magnet (Sweeper) to measure neutron-unbound states in oxygen isotopes close to the neutron dripline. While no excited states were observed in 24O, a resonance at 45(2) keV above the neutron separation energy was observed in 23O.Comment: 6 pages, 4 Figures, submitted to Proc. Int. Conf. on Proton Emitting Nuclei and Related Topics, PROCON0

Quasi-bound low energy tail of resonance

International audienceGround states of particle-unbound nuclei are seen as resonances. According to the Heisenberg's uncertainty principle, the shorter is the lifetime of the state the broader is the resonance. The Breit-Wigner function describes perfectly the shape of the resonance when energy-dependent partialwidths are used. In the low energy tail of a resonance, close to the particle-emission threshold, the partial-width for the emission of a charged particle through the Coulomb barrier is dramatically reduced. In this region of the resonance, the charged particle could be trapped inside the unboundnucleus. This idea will be discussed in more details and experimental aspects will be given