The N = 16 spherical shell closure in 24O

K. Tshoo; Y. Satou; H. Bhang; S. Choi; T. Nakamura; Y. Kondo; S. Deguchi; Y. Kawada; N. Kobayashi; Y. Nakayama; K. N. Tanaka; N. Tanaka; N. Aoi; M. Ishihara; T. Motobayashi; H. Otsu; H. Sakurai; S. Takeuchi; Y. Togano; K. Yoneda; Z. H. Li; F. Delaunay; J. Gibelin; F. M. Marqués; N. A. Orr; T. Honda; M. Matsushita; T. Kobayashi; Y. Miyashita; T. Sumikama; K. Yoshinaga; S. Shimoura; D. Sohler; T. Zheng; Z. X. Cao

doi:10.1103/physrevlett.109.022501

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arXiv · 1205.5657

The N = 16 spherical shell closure in 24O

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Abstract

The unbound excited states of the neutron drip-line isotope 24O have been investigated via the 24O(p,p')23O+n reaction in inverse kinematics at a beam energy of 62 MeV/nucleon. The decay energy spectrum of 24O* was reconstructed from the momenta of 23O and the neutron. The spin-parity of the first excited state, observed at Ex = 4.65 +/- 0.14 MeV, was determined to be Jpi = 2+ from the angular distribution of the cross section. Higher lying states were also observed. The quadrupole transition parameter beta2 of the 2+ state was deduced, for the first time, to be 0.15 +/- 0.04. The relatively high excitation energy and small beta2 value are indicative of the N = 16 shell closure in 24O.

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K. Tshoo, Y. Satou, H. Bhang, S. Choi, T. Nakamura, Y. Kondo, S. Deguchi, Y. Kawada, N. Kobayashi, Y. Nakayama, K. N. Tanaka, N. Tanaka, N. Aoi, M. Ishihara, T. Motobayashi, H. Otsu, H. Sakurai, S. Takeuchi, Y. Togano, K. Yoneda, Z. H. Li, F. Delaunay, J. Gibelin, F. M. Marqués, N. A. Orr, T. Honda, M. Matsushita, T. Kobayashi, Y. Miyashita, T. Sumikama, K. Yoshinaga, S. Shimoura, D. Sohler, T. Zheng, Z. X. Cao. 2012-05-25. The N = 16 spherical shell closure in 24O. https://doi.org/10.1103/physrevlett.109.022501

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