Pion nucleon interaction in a covariant hadron exchange model

Mar, 2000
41 pages
Published in:
  • Phys.Rev.C 61 (2000) 054003
e-Print:
Report number:
  • NIKHEF-99-021,
  • THU-99-25

Citations per year

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Abstract:
We develop a relativistic covariant and unitary description of the pion-nucleon interaction in a hadron-exchange model. The model is based on the solution of a dimensionally reduced (quasipotential) Bethe-Salpeter equation for the partial-wave off-shell πN\pi N scattering amplitudes with the potential consisting of the field-theoretical ss- and uu-channel nucleon, Roper, Delta, D13D_{13}, S11S_{11} exchanges, and the tt-channel ρ\rho and σ\sigma meson exchanges. The contributions of the spin-3/2 Delta and D13D_{13} resonances are treated within the Rarita-Schwinger formalism and different forms of the πNΔ\pi N\Delta vertex are investigated. The free parameters of the model are fitted to the πN\pi N phase-shift data of the KH80 and SM95 partial-wave analyses in the region up to 600 MeV pion kinetic energy. The resulting on-shell solution provides a good description of the πN\pi N scattering lengths, as well as the energy behavior of the S, P, and D partial waves. The sensitivity of the phase shifts on various model-dependent effects is examined.
  • pi nucleon: interaction
  • hadron: exchange
  • effective Lagrangian
  • invariance: Lorentz
  • unitarity
  • pi nucleon: scattering amplitude
  • partial wave analysis
  • Bethe-Salpeter equation
  • pi nucleon: scattering length
  • model: quasipotential