Study of cosmic ray events with high muon multiplicity using the ALICE detector at the CERN Large Hadron Collider

Adam, J. and Antičić, Tome and Erhardt, Filip and Gotovac, Sven and Mudnić, Eugen and Planinić, Mirko and Poljak, Nikola and Simatović, Goran and Utrobičić, Antonija and Vicković, Linda and Zyzak, M. (ALICE Collaboration) (2016) Study of cosmic ray events with high muon multiplicity using the ALICE detector at the CERN Large Hadron Collider. Journal of Cosmology and Astroparticle Physics, 2016 (1). pp. 32-1. ISSN 1475-7516

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Abstract

ALICE is one of four large experiments at the CERN Large Hadron Collider near Geneva, specially designed to study particle production in ultra-relativistic heavy-ion collisions. Located 52 meters underground with 28 meters of overburden rock, it has also been used to detect muons produced by cosmic ray interactions in the upper atmosphere. In this paper, we present the multiplicity distribution of these atmospheric muons and its comparison with Monte Carlo simulations. This analysis exploits the large size and excellent tracking capability of the ALICE Time Projection Chamber. A special emphasis is given to the study of high multiplicity events containing more than 100 reconstructed muons and corresponding to a muon areal density ρμ>5.9 m −2. Similar events have been studied in previous underground experiments such as ALEPH and DELPHI at LEP. While these experiments were able to reproduce the measured muon multiplicity distribution with Monte Carlo simulations at low and intermediate multiplicities, their simulations failed to describe the frequency of the highest multiplicity events. In this work we show that the high multiplicity events observed in ALICE stem from primary cosmic rays with energies above 1016 eV and that the frequency of these events can be successfully described by assuming a heavy mass composition of primary cosmic rays in this energy range. The development of the resulting air showers was simulated using the latest version of QGSJET to model hadronic interactions. This observation places significant constraints on alternative, more exotic, production mechanisms for these events.

Item Type: Article
Keywords: cosmic ray ; high muon multiplicity ; ALICE ; CERN
Date: 19 January 2016
Subjects: NATURAL SCIENCES > Physics
Additional Information: Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received August 7, 2015. Accepted December 17, 2015. Published January 19, 2016.
Divisions: Faculty of Science > Department of Physics
Publisher: IOP Publishing
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 23 Feb 2018 16:24
Last Modified: 23 Feb 2018 16:43
URI: http://digre.pmf.unizg.hr/id/eprint/5766

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