Effective interactions for nucleon-nucleus scattering above 300 MeV

Journal Article · Fri Jun 01 00:00:00 EDT 1990 · Physical Review, C (Nuclear Physics); (USA)

DOI:https://doi.org/10.1103/PhysRevC.41.2816· OSTI ID:6804176

Ray, L ^[1]

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1. Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (US)

A nonrelativistic nucleon-nucleon ({ital NN}) coupled channels isobar model is used to calculate nuclear medium corrections to the first-order Watson optical potential for nucleon-nucleus scattering. The {ital NN} interaction includes {pi}, 2{pi}, {rho}, {eta}, and {omega} exchange for the pure nucleonic sector, one-pion exchange for nucleon-isobar coupling, and phenomenological short-range interactions for both the diagonal and coupling terms. Good fits to {ital NN} elastic phase shifts from 0--1 GeV have been obtained with this model. The specific nuclear medium effects studied here include Pauli blocking of intermediate nucleon scattering states and off-shell binding energy shifts. On-momentum-shell matrix elements of the density dependent, effective {ital NN} {ital t} matrix are used to calculate the local proton-nucleus optical potential assuming the local density approximation. The model is applied to proton elastic scattering from {sup 16}O, {sup 40}Ca, {sup 48}Ca, and {sup 208}Pb at 320, 400, 500, 650, and 800 MeV and the predictions are compared with available data. In general, the medium modifications significantly affect the nonrelativistic predictions, even at 800 MeV, and bring about a substantial, overall improvement in the description of differential cross section and spin observable data. The improvements occur for each case and at all angles studied, but the agreement is most successful for forward angle differential cross sections and for spin observable data from 1 to 3 fm{sup {minus}1}. Deficiencies remain in the density dependent, nonrelativistic predictions for the forward angle spin observables where relativistic models are quite successful. The relation of this work to other nonrelativistic models which include nuclear medium corrections, off-shell effects, and full-folding contributions is also discussed.

• OSTI ID: 6804176
• Journal Information: Physical Review, C (Nuclear Physics); (USA), Journal Name: Physical Review, C (Nuclear Physics); (USA) Vol. 41:6; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR MOMENTUM
BARYON REACTIONS
BARYON-BARYON INTERACTIONS
CALCIUM 40 TARGET
CALCIUM 48 TARGET
CHARGED-PARTICLE REACTIONS
COUPLED CHANNEL THEORY
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELASTIC SCATTERING
ENERGY RANGE
HADRON REACTIONS
HADRON-HADRON INTERACTIONS
INTERACTIONS
ISOBAR MODEL
LEAD 208 TARGET
MATHEMATICAL MODELS
MEV RANGE
MEV RANGE 100-1000
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEON-NUCLEON INTERACTIONS
OXYGEN 16 TARGET
PARTICLE INTERACTIONS
PARTICLE MODELS
PARTICLE PROPERTIES
PHASE SHIFT
PROTON REACTIONS
SCATTERING
SPIN
TARGETS