Three-body dynamics on pp → pp and pp → pn π+ processes below 1 GeV

Abstract

pp scattering and ifpp → pnπ + reaction at incident laboratory energies ifT L ⩽ 1 GeV and T L = 400–800 MeV respectively are studied in the framework of the πNN dynamics where the three-body calculation is made with major NN and πN forces input. Additionally, the backward-going pion contribution at the πN Δ vertex, the πN- ρN coupling, the heavy-meson exchange in the NN → NN driving term and the effect of the off-shell structure in the πN- ρN P 33 interaction are taken into account. Various kinds of differential cross sections and polarizations of the pp → pn π + reaction are reasonably reproduced. The result for pp-scattering phase parameters is also presented. We make the Argand plot of the J p = 2 + and 3 − amplitudes and find a clear anti-clockwise looping. This indicates theoretical evidence in favor of the existence of the πNN resonances in these eigenstates.