Doorway state approximation and sign correlations in parity nonconservation in compound neutron resonances

Journal Article · Tue Dec 01 04:00:00 EST 1992 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.46.2582· OSTI ID:7199187

Auerbach, N ^[1]; Bowman, J D ^[2]

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1. National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)
2. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

The nonzero average parity-nonconserving longitudinal analyzing powers for {ital p}-wave neutron resonances in compound nuclear systems are analyzed within the giant {ital J}=0{sup {minus}} resonance doorway model. Assuming that the parity-nonconservation interaction can be approximated by a one-body operator of the type {sigma}{center dot}{bold p}, we find that the observed fixed sign of the asymmetry arises naturally within the doorway model. The {ital J}=0{sup {minus}} giant resonance does not enhance the size of the constant asymmetry. The model prediction for the average symmetry is shown to be similar to that obtained in the single-particle model. In particular, if one retains only the first-order contribution to the analyzing power, a very large single-particle matrix element {l angle}4{ital p}{sub 1/2}{vert bar}{ital V}{sub pv}{vert bar}5{ital s}{sub 1/2}{r angle}{congruent}75{plus minus}50 eV is needed to reproduce the observed average asymmetry. This large value is in contradiction with the value of 2 eV estimated from the experimentally measured spreading width of the parity-violating interaction using the doorway model.

• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 7199187
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 46:6; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
BARYON REACTIONS
COMPOUND-NUCLEUS REACTIONS
CORRELATIONS
DATA ANALYSIS
EVEN-EVEN NUCLEI
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HEAVY NUCLEI
ISOTOPES
MATHEMATICAL MODELS
NEUTRON REACTIONS
NUCLEAR REACTIONS
NUCLEAR STRUCTURE
NUCLEI
NUCLEON REACTIONS
P WAVES
PARITY
PARTIAL WAVES
PARTICLE MODELS
PARTICLE PROPERTIES
RADIOISOTOPES
SINGLE-PARTICLE MODEL
SPONTANEOUS FISSION RADIOISOTOPES
THORIUM 232
THORIUM ISOTOPES
YEARS LIVING RADIOISOTOPES