Neutron decay spectroscopy of neutron-rich oxygen isotopes

Neutron decay spectroscopy of neutron-rich oxygen isotopes has been performed using the two-proton knock-out reaction 9Be(26Ne,X)24,23,22O. A combination of the knock-out of valence and core protons can explain the three observed spectra. These knock-out processes are selective and preferentially populate hole states. The observed narrow resonance state in 23O at an excitation energy of 2.8(1) MeV was assigned to the 5/2+ state. * Corresponding author. E-mail address: [email protected] (N. Frank). 1 Present address: Physics Department, Illinois Wesleyan University, Bloomington, IL 61701, USA. 2 Present address: Laboratoire de Physique Corpusculaire, IN2P3, 14050 Caen, France. 3 Present address: Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA. 4 Present address: Nishina Center for Accelerator Based Science, RIKEN, Wako, Saitama 351-0198, Japan. 0375-9474/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.nuclphysa.2008.09.009 200 N. Frank et al. / Nuclear Physics A 813 (2008) 199–211 © 2008 Elsevier B.V. All rights reserved. PACS: 21.10.Pc; 23.90.+w; 25.60.Gc; 29.30.Hs