[en] The hypothesis previously put forth in the literature that alignment of spots on films that is observed in cosmic-ray emulsion experiments is related to a predominant jet character of events at ultrahigh energies is verified. The Monte Carlo PYTHIA generator, which is known to have provided good results in describing jet events in hadron-hadron interactions, is used in the present analysis. Because of a strong correlation between the directions of jet axes and particle momenta (colinearity) in them, the estimated degree of alignment of spots in jet events is substantially higher than that in a random sample of spots disposed chaotically on an x-ray film. For primary-interaction altitudes and collision energies satisfying some specific constraints, the degree of alignment appears to be strongly dependent on the hardness of the process and on the threshold for the total energy of selected clusters, increasing as they grow

[en] It is assumed that the ridge effect observed by the CMS Collaboration in proton-proton collisions at the LHC and the phenomenon observed by the Pamir Collaboration in emulsion experiments with cosmic rays and characterized by the alignment of spots on a film is a manifestation of the same as-yet-unknown mechanism of the emergence of a coplanar structure of events. A large coplanar effect at the LHC in the region of forward rapidities is predicted on the basis of this hypothesis and an analysis of experimental data.

[en] Data on most energetic particles in EAS cores (γ-ray-hadron families) obtained with XRECs at superhigh energies in stratospheric and high-mountain experiments are discussed. Transverse size and alignment of most energetic subcores in γ-h families are considered. Lateral features of γ-ray families are shown to be dependent on pt(x_Lab) at 0.05 < or approx. x_Lab < or approx. 0.20 in h-A interactions. Features of interactions at E₀ > or approx. 10¹⁵ are formulated.

[en] This paper focuses on the basic principles of the muon radiography method, reviews the major muon radiography experiments, and presents the first results in Russia obtained by the authors using this method based on emulsion track detectors. (instruments and methods of investigation)

[en] A gamma-hadron superfamily of cosmic-rays created by a primary cosmic-ray particle with energy above 10¹⁶ eV was detected at an altitude of 30 km by a stratospheric balloon-borne emulsion chamber. Being of superhigh energy, this event is the unique example in the world statistics of practically pure nuclear interactions in the energy range unattainable for modern accelerators. The present analysis allowed one to estimate the interaction height above the chamber and transverse momenta of the secondaries produced in the interaction. The mean value of transverse momenta appears to be very large (< p_t> > 2.5 GeV/c)

[en] Cosmic ray muon radiography is a novel technique for imaging the internal structures of massive objects. It exploits the capability of high energy muons from cosmic-rays in order to obtain a density map of investigated object and trying to guess information on the variation in the density distribution. Nuclear emulsions are tracking detectors well suited to be employed in this context since they have an excellent angular resolution (few mrad), they are cheap, compact and robust, easily transportable, able to work in harsh environments, and do not require power supply. This work presents the first successful results in the field of muon radiography in Russia with nuclear emulsions

[en] Cosmic ray muonography is a novel technique for imaging of the internal structures of large natural and industrial objects. It exploits the capability of high energy muons from cosmic rays to penetrate large thicknesses of large subjects to be studied, in order to obtain a density map. It uses muon flux attenuation and absorption in materials of investigated objects. Nuclear emulsions are tracking detectors well suited to be employed in muonography for investigations of inner structure of large objects up to kilometers size, since emulsions have firstly an excellent angular resolution, they are compact and robust, do not require power supply. The muonography methods are applied to study one of UNESCO world heritage objects, the unusual building in the Naryn-Kala citadel hidden underground. The use of nuclear emulsions as probing radiation detectors provides for a uniquely high resolution capacity of recording instrumentation combined with the potential of modern image analysis methods giving 3D reconstruction of the internal structures of the investigated object.

[en] Direct Dark Matter searches are nowadays one of the most fervid research topics with many experimental efforts devoted to the search for nuclear recoils induced by the scattering of Weakly Interactive Massive Particles (WIMPs). Detectors able to reconstruct the direction of the nucleus recoiling against the scattering WIMP are opening a new frontier to possibly extend Dark Matter searches beyond the neutrino background. Exploiting directionality would also prove the galactic origin of Dark Matter with an unambiguous signal-to-background separation. Indeed, the angular distribution of recoiled nuclei is centered around the direction of the Cygnus constellation, while the background distribution is expected to be isotropic. Current directional experiments are based on gas TPC whose sensitivity is limited by the small achievable detector mass. In this paper we present the discovery potential of a directional experiment based on the use of a solid target made of newly developed nuclear emulsions and of optical read-out systems reaching unprecedented nanometric resolution. (orig.)