Characterization of the varying flux of atmospheric muons measured with the Large Volume Detector for 24 years

Autor:	Agafonova, N. Yu., Aglietta, M., Antonioli, P., Ashikhmin, V. V., Bari, G., Bruno, G., Dobrynina, E. A., Enikeev, R. I., Fulgione, W., Galeotti, P., Garbini, M., Ghia, P. L., Giusti, P., Kemp, E., Malgin, A. S., Molinario, A., Persiani, R., Pless, I. A., Rubinetti, S., Ryazhskaya, O. G., Sartorelli, G., Shakiryanova, I. R., Selvi, M., Taricco, C., Trinchero, G. C., Vigorito, C. F., Yakushev, V. F., Zichichi, A.
Rok vydání:	2019
Předmět:	Astrophysics - High Energy Astrophysical Phenomena Astrophysics - Instrumentation and Methods for Astrophysics High Energy Physics - Experiment Physics - Instrumentation and Detectors
Druh dokumentu:	Working Paper
DOI:	10.1103/PhysRevD.100.062002
Popis:	The Large Volume Detector (LVD), hosted in the INFN Laboratori Nazionali del Gran Sasso, is triggered by atmospheric muons at a rate of $\sim 0.1$~Hz. The data collected over almost a quarter of century are used to study the muon intensity underground. The 50-million muon series, the longest ever exploited by an underground instrument, allows for the accurate long-term monitoring of the muon intensity underground. This is relevant as a study of the background in the Gran Sasso Laboratory, which hosts a variety of long-duration, low-background detectors. We describe the procedure to select muon-like events as well as the method used to compute the exposure. We report the value of the average muon flux measured from 1994 to 2017: $\mathrm{I_{\mu}^0 = 3.35 \pm 0.0005^{stat}\pm 0.03^{sys} \cdot 10^{-4} ~m^{-2} s^{-1}}$. We show that the intensity is modulated around this average value due to temperature variations in the stratosphere. We quantify such a correlation by using temperature data from the European Center for Medium-range Weather Forecasts: we find an effective temperature coefficient $\mathrm{\alpha_{T}} = 0.94\pm0.01^{stat} \pm0.01^{sys}$, in agreement with other measurements at the same depth. We scrutinise the spectral content of the time series of the muon intensity by means of the Lomb-Scargle analysis. This yields the evidence of a 1-year periodicity, as well as the indication of others, both shorter and longer, suggesting that the series is not a pure sinusoidal wave. Consequently, and for the first time, we characterise the observed modulation in terms of amplitude and position of maximum and minimum on a year-by-year basis. Comment: 26 pages, 10 figures, 4 tables
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/1909.04579 Zobrazit plný text záznamu View this record from Arxiv