Kinematic aspects of pion-nucleus elastic scattering

Journal Article · Sun Aug 01 04:00:00 EDT 1982 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.26.605· OSTI ID:7061202

Weiss, D L; Ernst, D J

The inclusion of relativistic kinematics in the theory of elastic scattering of pions from nuclei is examined. The investigation is performed in the context of the first order impulse approximation which incorporates the following features: (1) Relative momentum are defined according to relativistic theories consistent with time reversal invariance. (2) The two-nucleon interaction is a new, multichannel, separable potential model consistent with the most recent data derived from a recent nonpotential model of Ernst and Johnson. (3) The recoil of the pion-nucleon interacting pair and its resultant nonlocality are included. (4) The Fermi integral is treated by an optimal factorization approximation. It is shown how a careful definition of an intrinsic target density leads to an unambiguous method for including the recoil of the target. The target recoil corrections are found to be large for elastic scattering from /sup 4/He and not negligible for scattering from /sup 12/C. Relativistic potential theory kinematics, kinematics which result from covariant reduction approaches, and kinematics which result from replacing masses by energies in nonrelativistic formulas are compared. The relativistic potential theory kinematics and covariant reduction kinematics are shown to produce different elastic scattering at all pion energies examined (T/sub ..pi../<300 MeV). Simple extensions of nonrelativistic kinematics are found to be reasonable approximations to relativistic potential theory.

• Research Organization: Theoretical Division, Los Alamos National Laboratory, University of California, Los Alamos, New Mexico 87545
• OSTI ID: 7061202
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 26:2; ISSN PRVCA
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CARBON 12 TARGET
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
ELASTIC SCATTERING
ENERGY RANGE
HADRON REACTIONS
HELIUM 4 TARGET
IMPULSE APPROXIMATION
INVARIANCE PRINCIPLES
MESON REACTIONS
NUCLEAR REACTIONS
OPTICAL MODELS
PION REACTIONS
RECOILS
RELATIVISTIC RANGE
SCATTERING
T INVARIANCE
TARGETS