Longitudinal development of EAS in the energy range $10^{15} - 10^{20}$ eV by observation in the period of 1994-2014 at the Yakutsk

Abstract

The paper presents air shower data with Cherenkov radiation for the period 1994-2014. The energy interval 10 15 -10 20 eV and zenith angle θ = 0 • -55 • was considered. Dependence of average depth of maximum development of air showers on air shower energy are found. Fluctuation of X max are determined. Comparison of the experimental data with the calculations based on the QGSjetII-04 model for the primary proton and iron nuclei is presented. Mass composition of primary cosmic rays in the wide range of energies are made by interpolation.

The POEMMA (Probe of Extreme Multi-Messenger Astrophysics) observatory

“…Figure 9 shows the projected cross section measurements with JCAP06(2021)007 The two points are displaced for clarity. Also shown is a compilation of accelerator data converted to a proton-air cross section using the Glauber formalism and measurements [69][70][71][72][73][74][75][76][77], including the Telescope Array [78] and Pierre Auger Observatory [63] results. The proton-air cross sections for the QGSJet [79,80], Sibyll [81,82], and EPOS [83] Monte Carlo programs are also shown.…”

Muons in showers with energy $\boldsymbol{E_{0} \geq}$ 5 EeV and QGSjetII-04 and EPOS LHC models of hadronic interactions. Is there a muon deficit in the models?

“…Longitudinal development of ultrahigh-energy air showers is reconstructed at the Yakutsk array from measurements of the Cherenkov light LDF [10,18] and directly using track Cherenkov detectors [19,20]. These methods make it possible to determine the characteristics of the air shower development cascade curve X max .…”

“…The recently obtained irregularity in the CR spectrum at an energy of ∼ 10 17 eV [3][4][5], which is associated with the rigidity of particles of galactic origin, is of even greater interest, because the possibility of determining the boundary of the transition from galactic to extragalactic cosmic rays. The knowledge of the mass composition of primary particles in the region of 10 16 − 10 19 eV can help to establish the boundary between galactic and extragalactic cosmic rays [6][7][8][9].…”

“…The nuclear physics aspect includes the study of the interaction of primary particles with the nuclei of air atoms. First -obtaining the characteristics of an elementary event: the cross 032.1 section of inelastic interaction σ A−ai r , the average coefficient of inelasticity 〈K in 〉 and the multiplicity of secondary particles n ch -hadrons according to air shower registration data in the ultrahigh energy region [10][11][12][13]. Second -the study of the processes of interaction and decay of high-energy hadrons and the influence of these processes on muon and electromagnetic cascades in the development of air showers.…”

On irregularities in the cosmic ray spectrum of \(10^{16}-10^{18}\) eV range

“…The distinctive feature of the Small Cherenkov is that it measures several components of air showers like muons, electrons and Cherenkov radiation, unlike other compact arrays like KASCADE [8] or TUNKA [9]. Such hybrid measurements provide a broader outlook at the development of the shower, including longitudinal development, registering the spatial distribution of electrons, muons and Cherenkov light at sea level [10,11]. The longitudinal profile is measured via the flux of Cherenkov photons by the Cherenkov tracking detectors [11,12].…”