Neutron transition strengths of 2{sub 1}{sup +} states in the neutron-rich oxygen isotopes determined from inelastic proton scattering

Journal Article · Sun Mar 15 00:00:00 EDT 2009 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.79.034314· OSTI ID:21202738

Chien, Nguyen Dang ^[1]; Khoa, Dao T ^[1]

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1. Institute for Nuclear Science and Technique, VAEC, 179 Hoang Quoc Viet Rd., Nghia Do, Hanoi (Viet Nam)

A coupled-channel analysis of the {sup 18,20,22}O(p,p{sup '}) data has been performed to determine the neutron transition strengths of the 2{sub 1}{sup +} states in oxygen targets, using the microscopic optical potential and inelastic form factor calculated in the folding model. A complex density- and isospin-dependent version of the CDM3Y6 interaction was constructed, based on the Brueckner-Hartree-Fock calculation of nuclear matter, for the folding model input. Given an accurate isovector density dependence of the CDM3Y6 interaction, the isoscalar ({delta}{sub 0}) and isovector ({delta}{sub 1}) deformation lengths of the 2{sub 1}{sup +} states in {sup 18,20,22}O have been extracted from the folding model analysis of the (p,p{sup '}) data. A specific N dependence of {delta}{sub 0} and {delta}{sub 1} has been established which can be linked to the neutron shell closure occurring at N approaching 16. The strongest isovector deformation was found for the 2{sub 1}{sup +} state in {sup 20}O, with {delta}{sub 1} about 2.5 times larger than {delta}{sub 0}, which indicates a strong core polarization by the valence neutrons in {sup 20}O. The ratios of the neutron/proton transition matrix elements (M{sub n}/M{sub p}) determined for the 2{sub 1}{sup +} states in {sup 18,20}O have been compared with those deduced from the mirror symmetry, using the measured B(E2) values of the 2{sub 1}{sup +} states in the proton-rich {sup 18}Ne and {sup 20}Mg nuclei, to discuss the isospin impurity in the 2{sub 1}{sup +} excitation of the A=18, T=1 and A=20, T=2 isobars.

• OSTI ID: 21202738
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 79, Issue 3; Other Information: DOI: 10.1103/PhysRevC.79.034314; (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
COUPLED CHANNEL THEORY
DEFORMATION
DENSITY
EXCITATION
FOLDING MODEL
FORM FACTORS
HARTREE-FOCK METHOD
IMPURITIES
INTERACTIONS
ISOSPIN
ISOVECTORS
MAGNESIUM 20
MATRIX ELEMENTS
MIRRORS
NEON 18
NEUTRONS
NUCLEAR MATTER
OXYGEN
OXYGEN 18
OXYGEN 20
OXYGEN 22
POLARIZATION
PROTONS
SCATTERING
SYMMETRY
VALENCE