Mass composition of cosmic rays above 0.1 EeV by the Yakutsk array data

Abstract

The paper presents the results of the longitudinal development of extensive air showers (Xmax) of ultra-high energies and mass composition of cosmic rays. The measurements of Xmax are based on data from observations of the Cherenkov radiation at the Yakutsk array for the period 1974-2014. The cascade curves of individual showers and the depth of maximum Xmax were reconstructed over the energy range 10 16 -5.7·10 19 eV. It is shown that the displacement rate of the parameter dXmax / dE in the atmosphere is nonlinear and depends on the energy. Such a feature indicates a change in mass composition, which is confirmed by fluctuations of Xmax in this energy region. The composition of cosmic rays was determined by interpolation using the QGSJetII-04 model. * Electronic address: igor.petrov@ikfia.ysn.ru

Measuring temporal characteristics of the Cherenkov radiation signal from extensive air showers of cosmic rays with a wide field-of-view telescope addendum to the Yakutsk array

“…12 borrowed from [44]. It is in reasonable accord with a set of experiments: HiRes [45], PAO [46], TALE [47], Tunka [40], Yakutsk 2019 [48], LOFAR [44] within the interval (1.7 − 2.3) × 10 17 eV where the depth dispersion is confined to ∼ (640, 680) g/cm 2 .…”

Estimation of depth of maximum by relative muon content in air showers with energy greater than 5 EeV measured by the Yakutsk array

“…The results of the Yakutsk array for ln were obtained for four air shower components (Fig. 3) [26,44,53]. As can be seen from the figure, in the energy range of 5 EeV, the value of ln begins to increase, which indicates an increase in the mass composition.…”

“…Estimation of depth of maximum by relative muon content Igor Petrov the data of the Yakutsk array for other components: the Cherenkov light [26], scintillation detectors, muon LDF component [43] and the radio emission [44,45]. Also, the figure shows the data of the Auger [46,47], Telescope array [48,49], LOFAR [16] experiments and model calculations of the QGSJETII-04 [35], Sibyll 2.3c [50], EPOS-LHC [51].…”

“…The CR composition has been directly measured only up to energies 100 TeV in experiments on satellites and balloons [15][16][17][18][19][20][21][22]. At higher energies, the MC is studied at air shower experiments by indirect methods, analyzing the longitudinal development of individual showers [23][24][25][26] and the integral characteristics of showers at sea level [27][28][29][30]. The results obtained indirectly largely depend on the experimental equipment, the atmospheric conditions under which the measurements are carried out, the methods for processing experimental data, the model of hadronic interactions, and other factors.…”

On the nature of particles that produces extensive air showers with energy greater than 5 EeV

“…The Yakutsk array is medium in size, between compact arrays with an area of s ≥ 1 2 and huge arrays with s ≤ 1000 2 [18]. The energy range is 10 15 − 10 20 eV, which allows it to study both galactic and extragalactic cosmic rays.…”