Cosmic-muon flux and annual modulation in Borexino at 3800 m water-equivalent depth

Journal Article · Tue May 01 04:00:00 EDT 2012 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2012/05/015· OSTI ID:22280142

Bellini, G.; Avanzini, M. Buizza; Caccianiga, B.; D'Angelo, D. ^[1]; Benziger, J. ^[2]; Bick, D. ^[3]; Bonfini, G.; Cavalcante, P. ^[4]; Bravo, D. ^[5]; Cadonati, L. ^[6]; Calaprice, F.; Chavarria, A. ^[7]; Carraro, C.; Davini, S. ^[8]; Chepurnov, A. ^[9]; Derbin, A. ^[10]; Etenko, A. ^[11]; Feilitzsch, F. von ^[12]; Fomenko, K. ^[13]; Franco, D. ^[14] ; others, and

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1. Dipartimento di Fisica, Università di Milano and INFN Milano, via Celoria 16, I-20133 Milano (Italy)
2. Department of Chemical Engineering, Princeton University, Engineering Quadrangle, Princeton, NJ 08544-5263 (United States)
3. Institut für Experimentalphysik, Universität Hamburg, 22761 Hamburg (Germany)
4. Laboratori Nazionali del Gran Sasso, SS 17bis Km 18-910, I-67010 Assergi AQ (Italy)
5. Physics Department, Robeson Hall, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0435 (United States)
6. Physics Department, University of Massachusetts, Amherst, MA 01003 (United States)
7. Department of Physics, Princeton University, Jadwin Hall, Washington Road, Princeton, NJ 08544-0708 (United States)
8. Dipartimento di Fisica, Università di Genova and INFN Genova, via Dodecaneso 33, I-16146 Genova (Italy)
9. Institute of Nuclear Physics, Lomonosov Moscow State University, 119899, Moscow (Russian Federation)
10. St. Petersburg Nuclear Physics Institute, Gatchina (Russian Federation)
11. NRC Kurchatov Institute, Kurchatov Sq. 1, 123182 Moscow (Russian Federation)
12. Technische Universität München, James Franck Strasse E15, D-85747 Garching (Germany)
13. JINR, Joliot Curie str. 6, 141980 Dubna (Russian Federation)
14. Astroparticule et Cosmologie APC, 10 rue Alice Domon et Léonie Duquet, 75205 Paris cedex 13 (France)

We have measured the muon flux at the underground Gran Sasso National Laboratory (3800 m w.e.) to be (3.41±0.01)⋅10{sup −4}m{sup −2}s{sup −1} using four years of Borexino data. A modulation of this signal is observed with a period of (366±3) days and a relative amplitude of (1.29±0.07)%. The measured phase is (179±6) days, corresponding to a maximum on the 28{sup th} of June. Using the most complete atmospheric data models available, muon rate fluctuations are shown to be positively correlated with atmospheric temperature, with an effective coefficient α{sub T} = 0.93±0.04. This result represents the most precise study of the muon flux modulation for this site and is in good agreement with expectations.

• OSTI ID: 22280142
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 05 Vol. 2012; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
COSMIC MUONS
COSMIC RAY FLUX
FLUCTUATIONS
MODULATION
MUON DETECTION