Modulations of the Cosmic Muon Signal in Ten Years of Borexino Data

Abstract

We have measured the flux of cosmic muons in the Laboratori Nazionali del Gran Sasso at 3800\,m\,w.e. to be $(3.432\pm 0.003)\cdot 10^{-4}{\mathrm{m}}^{-2}{\mathrm{s}}^{-1}$ based on ten years of Borexino data acquired between May 2007 and May 2017. A seasonal modulation with a period of $(366.3\pm 0.6)\mathrm{d}$ and a relative amplitude of $(1.36\pm 0.04)\%$ is observed. The phase is measured to be $(181.7\pm 0.4)\mathrm{d}$, corresponding to a maximum at the 1${}^{\mathrm{st}}$ of July. Using data inferred from global atmospheric models, we show the muon flux to be positively correlated with the atmospheric temperature and measure the effective temperature coefficient ${\alpha }_{\mathrm{T}}=0.90\pm 0.02$. The origin of cosmic muons from pion and kaon decays in the atmosphere allows to interpret the effective temperature coefficient as an indirect measurement of the atmospheric kaon-to-pion production ratio $r_{\mathrm{K}/\pi }=0.11_{-0.07}^{+0.11}$ for primary energies above $18\mathrm{TeV}$. We find evidence for a long-term modulation of the muon flux with a period of $\sim 3000\mathrm{d}$ and a maximum in June 2012 that is not present in the atmospheric temperature data. A possible correlation between this modulation and the solar activity is investigated. The cosmogenic neutron production rate is found to show a seasonal modulation in phase with the cosmic muon flux but with an increased amplitude of $(2.6\pm 0.4)\%$.

arXiv comment30 pages, 16 figures, proofreading for publication in JCAP

References in corpus (35)

• Understanding the Lomb-Scargle Periodogram
• The Solar Cycle
• Energy Dependence of Pion and Kaon Production in Central Pb+Pb Collisions
• Precision measurement of the 7Be solar neutrino interaction rate in Borexino
• The Borexino detector at the Laboratori Nazionali del Gran Sasso
• Measurement of the solar 8B neutrino rate with a liquid scintillator target and 3 MeV energy threshold in the Borexino detector
• First evidence of pep solar neutrinos by direct detection in Borexino
• Observation of Geo-Neutrinos
• Uncertainties in Atmospheric Neutrino Fluxes
• Simultaneous Precision Spectroscopy of $pp$, ${}^7$Be, and $pep$ Solar Neutrinos with Borexino Phase-II
• Muon simulation codes MUSIC and MUSUN for underground physics
• Measurement of geo-neutrinos from 1353 days of Borexino
• Spectroscopy of geo-neutrinos from 2056 days of Borexino data
• Cosmogenic Backgrounds in Borexino at 3800 m water-equivalent depth
• Muon `Depth -- Intensity' Relation Measured by LVD Underground Experiment and Cosmic-Ray Muon Spectrum at Sea Level
• Absence of day-night asymmetry of 862 keV Be-7 solar neutrino rate in Borexino and MSW oscillation parameters
• Muon and Cosmogenic Neutron Detection in Borexino
• Cosmic-muon flux and annual modulation in Borexino at 3800 m water-equivalent depth
• Observation of muon intensity variations by season with the MINOS far detector
• The Search for the Sidereal and Solar Diurnal Modulations in the Total MACRO Muon Data Set
• Kaon Production and Kaon to Pion Ratio in Au+Au Collisions at $\snn=130$ GeV
• Halo-independent methods for inelastic dark matter scattering
• A Search for Periodicities in the ${}^8$B Solar Neutrino Flux Measured by the Sudbury Neutrino Observatory
• Improved measurement of ${}^8$B solar neutrinos with 1.5 kt y of Borexino exposure
• Cosmogenic 11C production and sensitivity of organic scintillator detectors to pep and CNO neutrinos
• The atmospheric charged kaon/pion ratio using seasonal variation methods
• Probe of the Solar Magnetic Field Using the "Cosmic-Ray Shadow" of the Sun
• Measurement of CNGS muon neutrino speed with Borexino
• Seasonal Modulation of the ${}^7$Be Solar Neutrino Rate in Borexino
• Muon-induced neutrons do not explain the DAMA data
• Cosmic-muon characterization and annual modulation measurement with Double Chooz detectors
• Flux Modulations seen by the Muon Veto of the GERDA Experiment
• The Gran Sasso muon puzzle
• DAMA vs. the annually modulated muon background
• Measurement of the muon-induced neutron seasonal modulation with LVD

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