Vanishing N=20 Shell Gap: Study of Excited States in {sup 27,28}Ne

Journal Article · Fri May 12 04:00:00 EDT 2006 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.96.182501· OSTI ID:20775237

Dombradi, Zs; Fueloep, Zs ^[1]; Elekes, Z ^[1]; Saito, A; Baba, H; Demichi, K; Gomi, T; Hasegawa, H; Kanno, S; Kawai, S; Kurita, K; Matsuyama, Y; Sakai, H K; Takeshita, E; Togano, Y; Yamada, K ^[2]; Aoi, N; Ishihara, M; Kishida, T; Kubo, T ^[3]

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1. Institute of Nuclear Research of the Hungarian Academy of Sciences, P.O. Box 51, Debrecen, H-4001 (Hungary)
2. Rikkyo University, 3 Nishi-Ikebukuro, Toshima, Tokyo 171 (Japan)
3. Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

This Letter reports on the {sup 1}H({sup 28}Ne,{sup 28}Ne) and {sup 1}H({sup 28}Ne,{sup 27}Ne) reactions studied at intermediate energy using a liquid hydrogen target. From the cross section populating the first 2{sup +} excited state of {sup 28}Ne, and using the previously determined B(E2) value, the neutron quadrupole transition matrix element has been calculated to be M{sub n}=13.8{+-}3.7 fm{sup 2}. In the neutron knockout reaction, two low-lying excited states were populated in {sup 27}Ne. Only one of them can be interpreted by the sd shell model while the additional state may intrude from the fp shell. These experimental observations are consistent with the presence of fp shell configurations at low excitation energy in {sup 27,28}Ne nuclei caused by a vanishing N=20 shell gap at Z=10.

• OSTI ID: 20775237
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 18 Vol. 96; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CROSS SECTIONS
EXCITATION
EXCITED STATES
HEAVY ION REACTIONS
HYDROGEN 1 TARGET
KNOCK-OUT REACTIONS
MATRIX ELEMENTS
NEON 27
NEON 28
NEUTRONS
NUCLEAR ELECTRIC MOMENTS
QUADRUPOLES
SHELL MODELS