First lifetime measurement of 21+ state in 12Be

N. Imai, N. Aoi, H. J. Ong, H. Sakurai, K. Demichi, H. Kawasaki, H. Baba, Zs Dombrádi, Z. Elekes, N. Fukuda, Zs Fülöp, A. Gelberg, T. Gomi, H. Hasegawa, K. Ishikawa, M. Ishihara, H. Iwasaki, E. Kaneko, S. Kanno, T. KishidaY. Kondo, T. Kubo, K. Kurita, S. Michimasa, T. Minemura, M. Miura, T. Motobayashi, T. Nakamura, M. Notani, T. K. Ohnishi, A. Saito, S. Shimoura, T. Sugimoto, M. K. Suzuki, E. Takeshita, S. Takeuchi, M. Tamaki, H. Watanabe, K. Yoneda

Research output: Contribution to journalArticle

28 Citations (Scopus)


The lifetime of the 21+ state at 2.1 MeV in 12Be has been measured using inelastic scattering of a 12Be beam at 43 MeV/nucleon with a gold target. Through the Doppler shift attenuation method, the mean-life of the 21+ state has been determined as 2.5 ± 0.7 (stat) ± 0.3 (syst) ps, which gives a B (E 2 ; 21+ → 0g.s.+) value of 4.9 ± 1.3 ± 0.5 in Weisskopf units. The result shows a large quadrupole strength in the ground state transition, providing further evidence on the disappearance of the N = 8 magic number. The B (E 2 ; 21+ → 0g.s.+) value together with the deformation length measured by proton inelastic scattering yields a neutron quadrupole matrix element two times larger than those for 14C and 16O.

Original languageEnglish
Pages (from-to)179-182
Number of pages4
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number3
Publication statusPublished - Mar 23 2009


  • Doppler-shift attenuation method
  • Radioactive beam experiment
  • Reduced matrix element

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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    Imai, N., Aoi, N., Ong, H. J., Sakurai, H., Demichi, K., Kawasaki, H., Baba, H., Dombrádi, Z., Elekes, Z., Fukuda, N., Fülöp, Z., Gelberg, A., Gomi, T., Hasegawa, H., Ishikawa, K., Ishihara, M., Iwasaki, H., Kaneko, E., Kanno, S., ... Yoneda, K. (2009). First lifetime measurement of 21+ state in 12Be. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 673(3), 179-182.