Decay Pattern of Pygmy States Observed in Neutron-Rich {sup 26}Ne

Journal Article · Fri Nov 21 04:00:00 EST 2008 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.101.212503· OSTI ID:21179926

Gibelin, J ^[1]; Beaumel, D; Blumenfeld, Y; Fortier, S; Frascaria, N; Lima, V; Scarpaci, J -A ^[1]; Motobayashi, T; Aoi, N; Baba, H; Fukuda, N; Gomi, T; Kubo, T; Takeuchi, S; Yanagisawa, Y; Yoshida, K ^[2]; Elekes, Z ^[3]; Ishikawa, K; Kondo, Y; Nakamura, T ^[4]

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1. Institut de Physique Nucleaire, IN2P3-CNRS, Universite Paris Sud, F-91406 Orsay (France)
2. RIKEN - Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
3. Institute of Nuclear Research of the Hungarian Academy of Sciences, PO Box 51, H-4001 Debrecen (Hungary)
4. Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551 (Japan)

Coulomb excitation of the exotic neutron-rich nucleus {sup 26}Ne on a {sup 208}Pb target was measured at 58 MeV/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 {sup 25}Ne+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{+-}0.16e{sup 2} fm{sup 2} 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.

• OSTI ID: 21179926
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 21 Vol. 101; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
COULOMB EXCITATION
DECOMPOSITION
DIFFERENTIAL CROSS SECTIONS
DIPOLES
LEAD 208 TARGET
MEAN-FIELD THEORY
MEV RANGE 10-100
NEON 25
NEON 26
NEUTRON EMISSION
NEUTRON-RICH ISOTOPES
NUCLEAR DECAY
PROBABILITY
SUM RULES