Neutron occupancy of 0d_5/2 orbital in ²⁴O

¹ RISP, Institute for Basic Science 70, Yusung-gu Daejeon 305-811, Korea
² Department of Physics and Astronomy, Seoul National University, Seoul, 151-742, Korea
³ Department of Physics, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
⁴ RIKEN Nishina Center, Saitama 351-0198, Japan
⁵ LPC-Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, 14050 Caen cedex, France
⁶ Department of Physics, Rikkyo University, Tokyo 171-8501, France
⁷ Department of Physics, Tohoku University, Aoba, Sendai Miyagi 980-8578, Japan
⁸ Department of Physics, Tokyo University of Science, Noda Chiba 278-8510, Japan
⁹ Center for Nuclear Study, University of Tokyo, Saitama 351-0198, Japan
¹⁰ Institute for Nuclear Research of the Hungarian Academy of Sciences, P.O.Box 51 H-4001 Debrecen, Hungary
¹¹ School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 , China
¹² Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 , Japan
¹³ Department of Physics, University of Tokyo, Tokyo 113-0033 , Japan

^a e-mail: tshoo@ibs.re.kr

Published online: 20 March 2014

Abstract

The partial one-neutron removal cross section of ²⁴O leading to the first excited state in ²³O has been measured to be 65.7 ± 5.3 mb with a proton target in inverse kinematics at the beam energy of 62 MeV/nucleon. The decay energy spectrum of the neutron unbound state of ²³O was reconstructed from the measured four momenta of ²²O and the emitted neutron. A sharp peak was observed at E_decay = 48 ± 3 keV, confirming the previous measurements. The measured partial longitudinal momentum distribution of ²³O^* showed the d-wave knockout character, providing a support for the J^π assignment of 5/2⁺ for this state. The spectroscopic factor for the neutrons in 0d_5/2 orbital was deduced, for the first time, to be C²S(0d_5/2) = 3.7 ± 0.3 (preliminary) by comparing with the result of Glauber model. The relatively large spectroscopic factor supports the N = 16 shell closure in the neutron drip-line nucleus ²⁴O.