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Three-particle model of the pion-nucleon system

Journal Article · · Physical Review. C, Nuclear Physics
;  [1]
  1. Department of Physics, University at Buffalo, State University of New York, Buffalo, New York 14260 (United States)
A relativistic, three-particle model of the pion-nucleon system is constructed in the instant form of relativistic quantum mechanics using the Bakamjian-Thomas procedure. The model space includes subspaces for the nucleon (N), the resonances {delta}=P{sub 33}(1232), P{sub 11}(1440), D{sub 13}(1520), S{sub 11}(1535), and S{sub 31}(1620), as well as {pi}N, {pi}{delta}, {eta}N, and {pi}{pi}N subspaces. The model specifies a Poincare invariant mass operator that includes vertex interactions that couple the various subspaces, as well as renormalization terms. Projection operator techniques are used to reduce the equations arising from this mass operator to a set of three-dimensional Lippmann-Schwinger integral equations that couple only the {pi}N, {pi}{delta}, and {eta}N channels. After a partial wave analysis these three-dimensional equations simplify to three coupled, one-dimensional integral equations for each partial wave. The mass operator interactions are derived from effective, hadronic Lagrangians that introduce a set of coupling constants. Cutoff functions are introduced to take into account the nonelementary nature of the particles in the model. These cutoff functions introduce a set of cutoff masses. The coupling constants, cutoff masses, and bare baryon masses are determined by fitting to a partial wave analysis of pion-nucleon elastic scattering up to a c.m. energy of W=1550 MeV.
OSTI ID:
21290041
Journal Information:
Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 2 Vol. 80; ISSN 0556-2813; ISSN PRVCAN
Country of Publication:
United States
Language:
English