Isospin distribution of quadrupole strength in /sup 118/Sn: Comparison with pion, nucleon, and electron scattering

Journal Article · Fri Apr 01 04:00:00 EST 1988 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.37.1537· OSTI ID:5158090

Brown, V R; Carr, J A; Madsen, V A; Petrovich, F

The isospin structure of the quadrupole strength in /sup 118/Sn is examined by a variety of means in an attempt to understand the surprisingly large amount of isovector strength extracted from some recent ..pi../sup -/..pi../sup +/ experiments in the excitation-energy region (below 2(h2..pi..)..omega..) expected for the isoscalar giant-quadrupole resonance. The ratio of the giant-quadrupole resonance neutron and proton multipole matrix elements for /sup 118/Sn determined from ..pi../sup -/..pi../sup +/ data is M/sub n/M/sub p/ = 1.9 +- 0.4 compared to calculations which range from 1.1 to about NZ (1.36). It is demonstrated that this large ratio has unrealistic consequences in random-phase approximation mixing of the giant states into the first 2/sup +/ state transition (core polarization), which has been independently studied by other probes and is in rather good agreement with quasiparticle random-phase approximation calculations, which have M/sub n/M/sub p/less than or equal toNZ for the isoscalar giant-quadrupole resonance. Quasiparticle random-phase approximation transition densities are used to calculate pion, proton, and neutron cross sections to the isoscalar giant-quadrupole resonance and the first 2/sup +/ state using microscopic reaction models. A comparison of B(E2) from the same structure model is made to the various data for the first 2/sup +/ transition and to the /sup 116/Sn(e,e') data on the isoscalar giant-quadrupole resonance. Although not completely conclusive because of the lack of reliable (e,e') data, the evidence from all these comparisons is that the ..pi../sup -/..pi../sup +/ results are at odds with the results of other probes and with nuclear structure theory and that the problem seems to be with the ..pi../sup +/ scattering results

• Research Organization: Lawrence Livermore National Laboratory, University of California, Livermore, California 94550
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5158090
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 37:4; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

653001* -- Nuclear Theory-- Nuclear Structure
Moments
Spin
& Models
653003 -- Nuclear Theory-- Nuclear Reactions & Scattering
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR MOMENTUM
BARYON REACTIONS
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
ELECTRON REACTIONS
ENERGY LEVELS
EVEN-EVEN NUCLEI
GIANT RESONANCE
HADRON REACTIONS
HYDRODYNAMIC MODEL
INELASTIC SCATTERING
INTERMEDIATE MASS NUCLEI
ISOTOPES
LEPTON REACTIONS
MATHEMATICAL MODELS
MATRIX ELEMENTS
MESON REACTIONS
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
PARITY
PARTICLE MODELS
PARTICLE PROPERTIES
PERTURBATION THEORY
PION REACTIONS
QUADRUPOLE MOMENTS
QUASI PARTICLES
RANDOM PHASE APPROXIMATION
RESONANCE
SCATTERING
SHELL MODELS
SPIN
STABLE ISOTOPES
STATISTICAL MODELS
TARGETS
THERMODYNAMIC MODEL
TIN 118
TIN 118 TARGET
TIN ISOTOPES