University of Oulu

Wladyslaw Henryk Trzaska et al 2020 J. Phys.: Conf. Ser.1468, 012085.

High-multiplicity muon events observed with EMMA array

Saved in:
Author: Trzaska, Wladyslaw Henryk1; Bezrukov, Leonid2; Enqvist, Timo1;
Organizations: 1Department of Physics, University of Jyväskylä, Finland
2Institute for Nuclear Research, Russian Academy of Sciences, Russia
3Moscow Institute of Physics and Technology, Russia
4Kerttu Saalasti Institute, University of Oulu, Finland
5Institute of Physics and Excellence Cluster PRISMA, Johannes Gutenberg-Universität Mainz, Germany
6nstitute for Nuclear Research, Russian Academy of Sciences, Russia
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.9 MB)
Persistent link:
Language: English
Published: IOP Publishing, 2020
Publish Date: 2020-11-30


High-multiplicity data, collected with a segmented scintillator array of the cosmic-ray experiment EMMA (Experiment with Multi-Muon Array), is presented for the first time. The measurements were done at the depth of 75 meters (210 m.w.e.) in the Pyhäsalmi mine in Finland. EMMA uses two types of detectors: drift chambers and plastic scintillation detectors. The presented data were acquired over the period between December, 2015 and April, 2018 using 128-800 plastic scintillator pixels probing the fiducial area of ˜100 m². The results are being interpreted in terms of CORSIKA simulations. Several events with densities in excess of 10 muons per m² were observed. At the next stage of the analysis, the high-multiplicity events will be matched with precision tracking data extracted from the multi-layer drift chambers of EMMA. Observation of high-density muon bundles was first reported by the LEP experiments: DELPHI, L3+C, and ALEPH. More recently, the ALICE experiment at CERN has provided new cosmic-ray results together with improved interpretation benefiting from the updated cross section values extracted from LHC results. While the tracking performance of ALICE is superior to EMMA, the duration of ALICE cosmic-ray measurements is very limited. Over the period of 2010–2018 the total exposure was only 93 days while EMMA, having a similar overburden provides a larger footprint and collects data continuously.

see all

Series: Journal of physics. Conference series
ISSN: 1742-6588
ISSN-E: 1742-6596
ISSN-L: 1742-6588
Issue: 1468
Article number: 012085
DOI: 10.1088/1742-6596/1468/1/012085
Host publication: 16th International Conference on Topics in Astroparticle and Underground Physics, TAUP 2019
Host publication editor: Nakahata, M.
Ohashi, M.
Conference: International Conference on Topics in Astroparticle and Underground Physics
Type of Publication: A4 Article in conference proceedings
Field of Science: 114 Physical sciences
115 Astronomy and space science
Copyright information: Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd.