The effect of the tendency towards the coplanar arrival of the most energetic particles and/or groups of particles in gamma–hadron families, observed in high-altitude and stratospheric experiments with X-ray emulsion chambers, is discussed. The experimental data are compared with calculations carried out within the framework of various versions of the FANSY 2.0 model, one of the versions of which reproduces the coplanar generation of the most energetic particles in hadron interactions at superhigh energies. The entire set of experimental data on the azimuthal characteristics of γ-ray–hadron families observed at levels of 25, 75, and 600 g/cm in the atmosphere cannot be explained even within the framework of the FANSY 2.0/2D model, which uses the hypothesis of a connection between coplanarity and the local 3D ↔ 2D evolution of the metric signature at ultrahigh energies.
R.A. Mukhamedshin (Wed,) studied this question.