One pion-exchange model for the pp → npπ+ reaction and its verification on a scale of differential pion spectra at initial energies from 0,66 to 1,0 GeV

A detailed comparison of all up-to-date collected 3rd order differential experimental data is made for pions produced in the pp → npπ+ reaction at approximately 660, 730, 800, 991 and 1000 MeV of the initial proton kinetic energies with the improved version of the one-pion exchange model-OPEM - for the given reaction. In this version all inputs from four Feynman pole diagrams and all their interferences are rigorously taken into account, the virtual πN-amplitude on its on-mass shell being approximated by Breit-Wigner type formula for 33-resonance. The applicability of the given OPEM version with form factor G(Ksub(i)sup(2))=9μsup(2)/(Ksub(i)sup(2)+10μsup(2)) is clearly demonstrated with an accuracy of about 10-15%, Ksub(i)sup(2) being the 4-momentum squared which is transferred by virtual pion inside the diagrams with indices i=1, 2, 3, 4 and μ is a pion mass