Analytical approach to the problem of constructing operators of effective pion-nucleon interaction at low and intermediate energies

Abstract

The dynamics of pion-nucleon scattering in the S 11 and S 31 states has been investigated on the basis of the analytical approach to construction of operators of effective interactions between compound systems of strongly interacting particles with allowance for inelasticity effects at incident pion kinetic energies T < 1.5–2.5 GeV. Information about the structure of discontinuities of partial πN-scattering amplitudes in the states under consideration is derived using the available phase-shift data and effective local potentials are constructed by solving the inverse scattering problem. The possibility of description of discontinuities of partial amplitudes at dynamical cuts using exchange mechanisms in the t-and u-scattering channels and contact interactions of the Lagrangian of the chiral perturbation theory is analyzed.