Isovector giant quadrupole resonance observed in [sup 89]Y([ital [rvec p]],[gamma])[sup 90]Zr

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.50.1528· OSTI ID:6953953

Godwin, M A; Hayward, E; Feldman, G; Kramer, L H; Weller, H R ^[1]; Dodge, W R ^[2]

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1. Duke University, Durham, North Carolina 27708 (United States) Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 (United States)
2. George Washington University, Washington, D.C. 20052 (United States)

The cross section and vector analyzing power for transitions to the ground and low-lying states in the [sup 89]Y([ital [rvec p]],[gamma])[sup 90]Zr reaction have been studied over the angular range [theta][gamma]=38.8[degree]--130[degree] at [ital E][sub [ital p]]=22.5 MeV and over the energy range [ital E][sub [ital p]]=18.5--28.5 MeV at [theta][sub [gamma]]=90[degree]. Angular distributions for the [gamma][sub 0] and [gamma][sub 1+2+3] transitions (i.e., to the first three strong single-particle excited states) reveal large asymmetries about [theta][sub [gamma]]=90[degree] in both [sigma]([theta]) and [sigma]([theta])[ital A][sub [ital y]]([theta]), suggesting [ital E]1/[ital E]2 interference effects. Legendre polynomial fits to these data yield nonzero coefficients of order [ital k]=3,4, thus confirming interference between the dominant [ital E]1 radiation and opposite parity [ital E]2 radiation. A transition-matrix element analysis of the [gamma][sub 0] angular distribution data, including [ital E]1 and [ital E]2 radiation, suggests a 28% [ital E]2 contribution, while a pure direct capture calculation predicts only 12% [ital E]2 strength. The energy dependence of [ital A][sub [ital y]](90[degree]) for the [gamma][sub 123] data is adequately described using the direct-semidirect model by including isovector quadropole resonances at [ital E][sub GQR]=27.5 MeV, built on each of the three states, with widths of [Gamma][sub GQR]=7.0 MeV and strengths which exhaust 100% of the isovector [ital E]2 energy-weighted sum rule for each state. These results provide strong evidence for collective [ital E]2 strength built on excited states in [sup 90]Zr, approximately at the energy predicted for the isovector giant quadrupole resonance, but are inconclusive concerning the ground-state transition.

• DOE Contract Number: FG05-91ER40619
• OSTI ID: 6953953
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 50:3; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

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663550 -- Nuclear Mass Ranges-- A=59-89-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANALYZING POWER
ANGULAR DISTRIBUTION
BARYON REACTIONS
BEAMS
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DISTRIBUTION
E1-TRANSITIONS
E2-TRANSITIONS
ELECTROMAGNETIC RADIATION
ENERGY DEPENDENCE
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
GAMMA RADIATION
GIANT RESONANCE
GROUND STATES
HADRON REACTIONS
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
ISOVECTORS
MATRIX ELEMENTS
MEV RANGE
MEV RANGE 10-100
MILLISEC LIVING RADIOISOTOPES
MULTIPOLE TRANSITIONS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
POLARIZED BEAMS
PROTON REACTIONS
RADIATIONS
RADIOISOTOPES
RESONANCE
STABLE ISOTOPES
TARGETS
TENSORS
VECTORS
YTTRIUM 89 TARGET
ZIRCONIUM 90
ZIRCONIUM ISOTOPES