## 2 <<Hadron-M>> Complex Installation
### Registration and Analysis of \"Hadron-M\" Experimental Data
However, FASER is searching for new light, long-lived and mostly weak-interacting particles that are produced at or close to the ATLAS interaction point, move along the beam collision axis line of sight, and then decay within the volume of FASER into visible decay products. Thus, the goals of the FASER experiment are not focused on the study of most energetic hadrons, which is what is considered in this paper. A certain contribution to these studies could be made by the \"Hadron-M\" installation, which is aimed at studying the EAS central core [64]. Research carried out at the \"Hadron-M\" installation is aimed at studying the most energetic particles to solve the fundamental problems of cosmic ray physics related to the nature and propagation of primary cosmic rays from their sources to the Earth. Considering that the \"Hadron-M\" installation has no analog in the world, it can qualitatively show new results in the problem of identifying the \"true\" properties penetrating the cosmic ray components due to the complex and diverse structure of the installed detectors and the depth of the ionization calorimeter. One of the tasks being solved at the \"Hadron-M\" installation relates to a study from the field of gamma-ray astronomy to calculate the trajectory from the observed EAS characteristics to the primary energy [48]. The gamma radiation detection method is based on the fact that the gamma block absorbs the electron-photon component (EPC) of cosmic rays, and the hadronic component, due to the small thickness of the gamma block, passes without interactions through the gamma block. Further interactions and generation of particles develop in the hadron block. Taking into account that the \"Hadron-M\" installation is located on uneven mountainous terrain, the new calculations in the standard method were introduced to find the coordinates of primary particles. To determine the coordinates of the primary particle, the installation data on the thickness of the atmosphere passed by the shower were used, such as: the zenith angle of arrival of the shower \(\theta\), the azimuth angle \(\varphi\) of the shower, the total number of particles in the shower \(\mathrm{N_{e}}\) at the observation level and their lateral distribution. The number of detectors available on the installation allows for the reduction of errors when finding angles. Knowledge of \(\theta\), \(\varphi\), EAS arrival time (UTC), and the geographical co-ordinates of the installation allows one to unambiguously determine the point of the celestial sphere from which the primary particle came. One of the topical tasks solved at the \"Hadron-M\" installation is the study of the interactions of hadrons with the nuclei of air atoms and the identification of their properties during the generation of secondary particles in the energy range \(E>10^{15}\) eV. To study the composition of primary cosmic radiation and the passage of EAS, as well as to confirm previously obtained results, it is necessary to collect statistical material, conduct and play several different cascades from hadrons and muons, taking into account the structure of the calorimeter and the method of registration of the \"Hadron-M\" installation; calculate the composition and spectra of hadrons and muons in the EAS core at the height of the Tien Shan high mountain station for different energies and charges of primary nuclei using various models, including the CORSIKA package; and carry out a comparative analysis with the experimental data of the \"Hadron-M\" installation.