https://doi.org/10.1140/epjc/s10052-010-1284-8
Regular Article - Experimental Physics
Measurement of the atmospheric muon charge ratio with the OPERA detector
1
INR—Institute for Nuclear Research of the Russian Academy of Sciences, 117312, Moscow, Russia
2
SINP MSU—Skobeltsyn Institute of Nuclear Physics of Moscow State University, 119992, Moscow, Russia
3
Kobe University, 657-8501, Kobe, Japan
4
Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics (LHEP), University of Bern, 3012, Bern, Switzerland
5
IPNL, Université Claude Bernard Lyon 1, CNRS/IN2P3, 69622, Villeurbanne, France
6
ETH Zurich, Institute for Particle Physics, 8093, Zurich, Switzerland
7
LPI—Lebedev Physical Institute of the Russian Academy of Sciences, 117924, Moscow, Russia
8
INFN Sezione di Padova, 35131, Padova, Italy
9
LAPP, Université de Savoie, CNRS/IN2P3, 74941, Annecy-le-Vieux, France
10
Hamburg University, 22761, Hamburg, Germany
11
Dipartimento di Fisica dell’Università di Salerno and INFN, 84084, Fisciano, Salerno, Italy
12
Dipartimento di Fisica dell’Università di Padova, 35131, Padova, Italy
13
Dipartimento di Fisica dell’Università di Bologna, 40127, Bologna, Italy
14
INFN Sezione di Bologna, 40127, Bologna, Italy
15
INFN Sezione di Napoli, 80125, Napoli, Italy
16
INFN—Laboratori Nazionali di Frascati dell’INFN, 00044, Frascati (Roma), Italy
17
IPHC, Université de Strasbourg, CNRS/IN2P3, CNRS/IN2P3, 67037, Strasbourg, France
18
INFN—Laboratori Nazionali del Gran Sasso, 67010, Assergi (L’Aquila), Italy
19
Dipartimento di Fisica dell’Università Federico II di Napoli, 80125, Napoli, Italy
20
INFN Sezione di Bari, 70126, Bari, Italy
21
Dipartimento di Fisica dell’Università dell’Aquila and INFN, 67100, L’Aquila, Italy
22
JINR—Joint Institute for Nuclear Research, 141980, Dubna, Russia
23
ITEP—Institute for Theoretical and Experimental Physics, 117218, Moscow, Russia
24
University of Münster, 48149, Münster, Germany
25
Nagoya University, 464-8602, Nagoya, Japan
26
Toho University, 274-8510, Funabashi, Japan
27
Department of Physics, Technion, 32000, Haifa, Israel
28
METU—Middle East Technical University, 06531, Ankara, Turkey
29
Fachbereich Physik der Universität Rostock, 18051, Rostock, Germany
30
IRB—Rudjer Boskovic Institute, 10002, Zagreb, Croatia
31
Gyeongsang National University, 900 Gazwa-dong, Jinju, 660-701, South Korea
32
Aichi University of Education, 448-8542, Kariya (Aichi-Ken), Japan
33
Dipartimento di Fisica dell’Università di Bari, 70126, Bari, Italy
34
Dipartimento di Fisica dell’Università di Roma “La Sapienza” and INFN, 00185, Roma, Italy
35
Utsunomiya University, 321-8505, Tochigi-Ken, Utsunomiya, Japan
36
IIHE, Université Libre de Bruxelles, 1050, Brussels, Belgium
* e-mail: sioli@bo.infn.it
Received:
14
December
2009
Revised:
17
February
2010
Published online:
23
March
2010
The OPERA detector at the Gran Sasso underground laboratory (LNGS) was used to measure the atmospheric muon charge ratio in the TeV energy region. We analyzed 403069 atmospheric muons corresponding to 113.4 days of livetime during the 2008 CNGS run. We computed separately the muon charge ratio for single and for multiple muon events in order to select different energy regions of the primary cosmic ray spectrum and to test the R
μ
dependence on the primary composition. The measured R
μ
values were corrected taking into account the charge-misidentification errors. Data have also been grouped in five bins of the “vertical surface energy” ℰ
μ
cos θ. A fit to a simplified model of muon production in the atmosphere allowed the determination of the pion and kaon charge ratios weighted by the cosmic ray energy spectrum.
© Springer-Verlag / Società Italiana di Fisica, 2010