Status of the Yakutsk air shower array and future plans

Abstract

The Yakutsk Extensive Air Shower Array has been continuously operating for more than 50 years (since 1970) and up until recently it has been one of world's largest ground-based instruments aimed at studying the properties of cosmic rays in the ultra-high energy domain. In this report we discuss results recently obtained at the array -on cosmic rays energy spectrum, mass composition and directional anisotropy -and how they fit into the world data. Special attention is paid to the measurements of muonic component of extensive air showers. Theoretical results of particle acceleration at shocks are also briefly reviewed. Future scientific and engineering plans on the array modernization are discussed. I. INTRODUCTIONThe only way to study the properties of cosmic rays (CR) with energies above ∼ 10 15 eV is by registering extensive air showers (EAS) -cascades of secondary particles produced by high-energy CRs hitting Earth's atmosphere. On one hand by studying the EAS properties one can investigate hadron interactions at energies unreachable for terrestrial particle acceleration technology. On the other hand -EAS method provides the basis for obtaining crucial information on primary CR properties: their energy spectrum, mass composition and distribution of arrival directions on the celestial sphere. Hence, EAS study is a dedicated area of CR physics at the intersection of astrophysics and nuclear physics.

Deep learning method for identifying mass composition of ultra-high-energy cosmic rays

“…Different models yield considerably different air shower properties at the ground level. Moreover, some experiments observe the excess of the observed muons signal as compared to the simulations [23][24][25][26][27], while others do not [28][29][30][31] (see [32] for a review). This imposes certain limitations on the use of hadronic interaction models for analyzing the actual experiment's data.…”