Meson-nucleus dynamics

Journal Article · Thu Oct 01 00:00:00 EDT 1992 · Annals of Physics (New York); (United States)

DOI:https://doi.org/10.1016/0003-4916(92)90349-Q· OSTI ID:5577510

Johnson, M B ^[1]; Ernst, D J ^[2]

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1. Los Alamos National Laboratory, NM (United States)
2. Texas A M Univ., College Station, TX (United States)

The diagrammatic perturbation theory for the interaction of a pion with a finite nucleus is developed. The theory allows the authors to identify the various pieces of the physics which are believed to be important and to put into a unifying language the understanding which is emerging from apparently diverse studies. The theory proposed here is arranged so that it maintains the use of the nearly free pion-nucleon T-matrix and contemporary nuclear structure work which utilizes a nucleon-nucleon Bethe-Goldstone g-matrix. Within this framework, the authors calculate the momentum space and without approximation of the first-order optical potential. This potential includes: (1) an exact performance of the Fermi-averaging integral (delta propagation); (2) covariant kinematics including the recoil of the nuclear target; (3) the use of invariant amplitudes and invariant normalizations and phase space factors; (4) the inclusion of the delta-nucleus interaction through a mean-spectral approximation; and (5) a realistic off-shell extrapolation of the pion-nucleon amplitude. The elastic scattering cross sections predicted by this potential are remarkably close to the data. The higher-order effects are classified and their inter-relationship discussed. Three of the higher-order corrections, Pauli effects, pion true-absorption, and short range correlation effects, are calculated and the success of the first-order potential is found to be validated by a large cancellation between the Pauli and true-absorption corrections. A detailed discussion of and comparison to alternate approaches to investigating pion-nucleus dynamics is provided. 130 refs., 24 figs., 1 tab.

• OSTI ID: 5577510
• Journal Information: Annals of Physics (New York); (United States), Journal Name: Annals of Physics (New York); (United States) Vol. 219:1; ISSN 0003-4916; ISSN APNYA6
• Country of Publication: United States
• Language: English

Related Subjects

663460* -- Meson- & Hyperon-induced Reactions & Scattering-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BETHE-GOLDSTONE EQUATION
CORRECTIONS
CROSS SECTIONS
ELASTIC SCATTERING
EQUATIONS
G MATRIX
HADRON-HADRON INTERACTIONS
INTERACTIONS
MATHEMATICAL SPACE
MATRICES
MESON-BARYON INTERACTIONS
MESON-NUCLEON INTERACTIONS
NUCLEAR STRUCTURE
PARTICLE INTERACTIONS
PARTICLE KINEMATICS
PERTURBATION THEORY
PHASE SPACE
PION-NUCLEON INTERACTIONS
S MATRIX
SCATTERING
SPACE