Experimental results are presented for study of collective and fractal properties of soft pion jets in the space of relative four-dimensional velocities. Significant decreasing is obtained for mean square of second particle distances from jet axis for pion-proton interactions at initial energies ∼ 3 GeV in comparison with hadron-nuclear collisions at close energies. The decreasing results in power dependence of distance variable on collision energy for range ∼ 2 − 4 GeV. The observation allows us to estimate the low boundary of manifestation of color degree of freedom in pion jet production. Cluster dimension values were deduced for pion jets in various reactions. Fractional values of this dimension indicate on the manifestation of fractal-like properties by pion jets. Changing of mean kinetic energy of jet particles and fractal dimension with initial energy increasing is consistent with suggestion for presence of color degrees of freedom in pion jet production at intermediate energies.

The effect of nucleon current contribution to nucleon magnetic moment is considered up to the fourth order of the coupling constant in the cut-off meson theory using the renormalization procedure as developed by Chew. The same parameters as employed to fit the meson-nucleon scattering data have been used here. It is found that the additional contribution due to this effect improves the previous theoretical results where only the mesonic current contribution has been taken into account.

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