Shape of {sup 44}Ar: Onset of deformation in neutron-rich nuclei near {sup 48}Ca

Journal Article · Wed Jul 15 00:00:00 EDT 2009 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.80.014317· OSTI ID:21293764

Zielinska, M ^[1]; Goergen, A; Clement, E; Korten, W; Dossat, C; Ljungvall, J; Obertelli, A; Theisen, Ch ^[1]; Delaroche, J -P; Girod, M ^[2]; Buerger, A ^[1]; Catford, W ^[3]; Iwanicki, J; Napiorkowski, P J; Srebrny, J; Wrzosek, K ^[4]; Libert, J ^[5]; PiePtak, D ^[6]; Rodriguez-Guzman, R ^[7]; Sletten, G ^[8]

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1. CEA Saclay, IRFU, Service de Physique Nucleaire, F-91191 Gif-sur-Yvette (France)
2. CEA, DAM, DIF, F-91297 Arpajon (France)
3. Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)
4. Heavy Ion Laboratory, University of Warsaw, PL-02-093 Warsaw (Poland)
5. Institut de Physique Nucleaire, IN2P3-CNRS/Universite Paris-Sud, F-91406 Orsay (France)
6. II WeiTI, Warsaw University of Technology (Poland)
7. Department of Physics, University of Jyvaeskylae, P. O. Box 35, FI-40014 Jyvaeskylae (Finland)
8. Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark)

The development of deformation and shape coexistence in the vicinity of doubly magic {sup 48}Ca, related to the weakening of the N=28 shell closure, was addressed in a low-energy Coulomb excitation experiment using a radioactive {sup 44}Ar beam from the SPIRAL facility at GANIL. The 2{sub 1}{sup +} and 2{sub 2}{sup +} states in {sup 44}Ar were excited on {sup 208}Pb and {sup 109}Ag targets at two different beam energies. B(E2) values between all observed states and the spectroscopic quadrupole moment of the 2{sub 1}{sup +} state were extracted from the differential Coulomb excitation cross sections, indicating a prolate shape of the {sup 44}Ar nucleus and giving evidence of an onset of deformation already two protons and two neutrons away from doubly magic {sup 48}Ca. New Hartree-Fock-Bogoliubov based configuration mixing calculations have been performed with the Gogny D1S interaction for {sup 44}Ar and neighboring nuclei using two different approaches: the angular momentum projected generator coordinate method considering axial quadrupole deformations and a five-dimensional approach including the triaxial degree of freedom. The experimental values and new calculations are furthermore compared to shell-model calculations and to relativistic mean-field calculations. The new results give insight into the weakening of the N=28 shell closure and the development of deformation in this neutron-rich region of the nuclear chart.

• OSTI ID: 21293764
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 80, Issue 1; Other Information: DOI: 10.1103/PhysRevC.80.014317; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR MOMENTUM
ARGON 44
CALCIUM 48
CONFIGURATION MIXING
COULOMB EXCITATION
CROSS SECTIONS
DEFORMED NUCLEI
DEGREES OF FREEDOM
GANIL CYCLOTRON
GENERATOR-COORDINATE METHOD
HARTREE-FOCK-BOGOLYUBOV THEORY
LEAD 208
MAGIC NUCLEI
MEAN-FIELD THEORY
NEUTRON-RICH ISOTOPES
NEUTRONS
PROTONS
QUADRUPOLE MOMENTS
RADIOACTIVE ION BEAMS
RELATIVISTIC RANGE
SHELL MODELS
SILVER 109