Decay pattern of pygmy states observed in neutron-rich Ne26

J. Gibelin, D. Beaumel, T. Motobayashi, Y. Blumenfeld, N. Aoi, H. Baba, Z. Elekes, S. Fortier, N. Frascaria, N. Fukuda, T. Gomi, K. Ishikawa, Y. Kondo, T. Kubo, V. Lima, T. Nakamura, A. Saito, Y. Satou, J. A. Scarpaci, E. TakeshitaS. Takeuchi, T. Teranishi, Y. Togano, A. M. Vinodkumar, Y. Yanagisawa, K. Yoshida

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Abstract

Coulomb excitation of the exotic neutron-rich nucleus Ne26 on a Pb208 target was measured at 58MeV/u in order to search for low-lying E1 strength above the neutron emission threshold. This radioactive beam experiment was carried out at the RIKEN Accelerator Research Facility. Using the invariant mass method in the Ne25+n channel, we observe a sizable amount of E1 strength between 6 and 10 MeV excitation energy. By performing a multipole decomposition of the differential cross section, a reduced dipole transition probability of B(E1)=0.49±0.16e2fm2 is deduced, corresponding to 4.9±1.6% of the Thomas-Reiche-Kuhn sum rule. For the first time, the decay pattern of low-lying strength in a neutron-rich nucleus is measured. The extracted decay pattern is not consistent with several mean-field theory descriptions of the pygmy states.

Original languageEnglish
Article number212503
JournalPhysical Review Letters
Volume101
Issue number21
DOIs
Publication statusPublished - Nov 19 2008

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Gibelin, J., Beaumel, D., Motobayashi, T., Blumenfeld, Y., Aoi, N., Baba, H., ... Yoshida, K. (2008). Decay pattern of pygmy states observed in neutron-rich Ne26. Physical Review Letters, 101(21), [212503]. https://doi.org/10.1103/PhysRevLett.101.212503