Multimuons in cosmic-ray events as seen in ALICE at the LHC

Abstract

ALICE is a large experiment at the CERN Large Hadron Collider. Located 52 meters underground, its detectors are suitable to measure muons produced by cosmic-ray interactions in the atmosphere. In this paper, the studies of the cosmic muons registered by ALICE during Run 2 (2015-2018) are described. The analysis is limited to multimuon events defined as events with more than four detected muons (N-mu > 4) and in the zenith angle range 0 degrees 100) obtained with QGSJET-II-04 and SIBYLL 2.3d is compatible with the data, while EPOS-LHC produces a significantly lower rate (55% of the measured rate). For both QGSJET-II-04 and SIBYLL 2.3d, the rate is close to the data when the composition is assumed to be dominated by heavy elements, an outcome compatible with the average energy E-prim similar to 10(17) eV of these events. This result places significant constraints on more exotic production mechanisms.