Polarized proton capture and the isovector giant quadrupole resonance in {sup 90}Zr

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Bulletin of the American Physical Society

OSTI ID:387266

Godwin, M A; Feldman, G; Hayward, E; H, Kramer L

Polarized proton capture experiments have been performed in an attempt to observe the Isovector Giant Quadrupole Resonance (IVGOR) in {sup 90}Zr. The cross section and vector analyzing power for transitions to the ground and low-lying states in the {sup 89}Y({tilde p}, {gamma}){sup 90}Zr reaction have been studied over the angular range over the energy range E{sub p} = 18.5-28.5 MeV (at {theta}{sub {gamma}} = 90{degrees}). A transition-matrix element analysis of the {gamma}{sub 0}E2 and E3 radiation, suggests a pure direct capture calculation predicts only 6% E2 strength. The A{sub y}(E) data at 90{degrees} for the {gamma}{sub 1+2+3} transitions (ie. to the first three strong single-particle excited states) depicts a resonance-like structure near ED = 23 MeV. These data are adequately described using the direct-semidirect (DSD) model by including IVGQ resonances at E{sub GQR} = 29.0 MeV built on each of the three states, with widths of E{sub GQR} = 5.5 MeV and strengths which exhaust 100% of the isovector E2 energy-weighted sum rule for each state. This same DSD calculation predicts a resonance structure in the {gamma}{sub 0} analyzing power near E{sub p} = 21 MeV, which is not seen in the data.

• DOE Contract Number: FG05-91ER40619
• OSTI ID: 387266
• Report Number(s): CONF-931044--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 9 Vol. 38; ISSN BAPSA6; ISSN 0003-0503
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CAPTURE
CROSS SECTIONS
GIANT RESONANCE
NUCLEAR STRUCTURE
PROTON REACTIONS
YTTRIUM 89 TARGET
ZIRCONIUM 90