On the dynamic mechanism of the Δ(1236) resonance production

It has been shown that the amplitudes of the reactions with production or formation of the Δ(1236) resonance have near the physical range a logarithmic singularity corresponding to the triangular Feinman diagram with the intermediate state nucleon + meson. The singularity causes the peak in the cross section for effective nucleon and π meson masses, the width and the quantum numbers coinciding with the Δ(1236) resonance parameters. This permits to infer that the mechanism of the formation of the resonance presents multiple scattering of a virtual pion and a nucleon in the state with j=3/2, whereas from the mathematical point of view the mechanism is due to the logarithmic singularity of the integral equation for the amplitude