Ct. Hung et al., A RELATIVISTIC MESON-EXCHANGE MODEL OF PION-NUCLEON SCATTERING, Journal of physics. G, Nuclear and particle physics, 20(9), 1994, pp. 1531-1536
Pion-nucleon scattering is investigated using the Kadyshevsky three-di
mensional reduction of the Bethe-Salpeter equation. The resulting pote
ntial includes the direct and crossed N, Delta terms, and the t-channe
l sigma- and rho-exchange terms. The nucleon pole condition is imposed
to define the renormalization of the nucleon mass and the pi NN coupl
ing constant. A mixture of the scalar and vector sigma pi pi couplings
is introduced to simulate the effect of the broad width of the s-wave
correlated two-pion exchange mechanism. Good descriptions of the pi N
phase shifts up to 400 MeV have been obtained in all S- and P-waves.
The off-shell behaviours for our model differ significantly from those
obtained using different reduction schemes.