Investigating cosmic rays and air shower physics with IceCube/IceTop

Abstract

Abstract. IceCube is a cubic-kilometer detector in the deep ice at South Pole. Its square-kilometer surface array, IceTop, is located at 2800 m altitude. IceTop is large and dense enough to cover the cosmic-ray energy spectrum from PeV to EeV energies with a remarkably small systematic uncertainty, thanks to being close to the shower maximum. The experiment offers new insights into hadronic physics of air showers by observing three components: the electromagnetic signal at the surface, GeV muons in the periphery of the showers, and TeV muons in the deep ice. The cosmic-ray flux is measured with the surface signal. The mass composition is extracted from the energy loss of TeV muons observed in the deep ice in coincidence with signals at the surface. The muon lateral distribution is obtained from GeV muons identified in surface signals in the periphery of the shower. The energy spectrum of the most energetic TeV muons is also under study, as well as special events with laterally separated TeV muon tracks which originate from high-p T TeV muons. A combination of all these measurements opens the possibility to perform powerful new tests of hadronic interaction models used to simulate air showers. The latest results will be reviewed from this perspective.

Muon content of extensive air showers: comparison of the energy spectra obtained by the Sydney University Giant Air-shower Recorder and by the Pierre Auger Observatory

“…This is in line with earlier results of the HiRes/MIA experiment [7] obtained for E 10 17 eV. While preliminary IceTop results [8] for GeV muons and 10 15 eV E 10 17 eV suggested that no excess is seen, they have been superseded by newer preliminary results [9] demonstrating the rise of the muon excess near 10 17 eV, consistent with the excess seen by HiRes/MIA (see also discussion in Ref. [10]).…”

Progress in high-energy cosmic ray physics

“…The most recent SIBYLL model including this effect finds indeed a significant enhancement in the number of muons produced in the shower [101]. Note that since the suppression of the electromagnetic component by an enhanced ρ 0 production is a cumulative effect, depending on the number of generations of hadronic interactions that happen before the charged pions decay, the muon excess is expected to be reduced for lower energy primaries, and indeed no indications of a significant muon excess have been reported at energies below 0.1 EeV (although there is always an interplay between the expected number of muons and the inferred CR composition) [102,103].…”

Probing particle physics with IceCube

“…15. There is definitely complementary information from neutrino telescopes to be added to the efforts in understanding hadronic interactions using air shower arrays and heavy-ion and hadronic accelerator experiments [104,105].…”