NegativeP′-pole parameters and vanishing total cross sections in high energy πN scattering

Abstract

In πN forward scattering the conventionalP′-pole can be simulated by two vacuum poles with α(0)<0 and different signs of the residues. In the regions −0.3≦ α _p ′(0)≦−0.1 and −0.8≦α _p ′'(0)≦−0.4 the practically identical fits to the πN scattering data from 8 to 65 GeV/c yield 0.98≦α _p (0)<1. The dispersion theoretical sum rule for the scattering lengtha ⁽⁺⁾ is fulfilled because of the negativeP′ residue; it is used as a finite-energy sum rule withN=8 GeV/c.