Muon “depth-intensity” relation measured by the LVD underground experiment and cosmic-ray muon spectrum at sea level

Abstract

We present an analysis of muon events with all muon multiplicities collected during 21804 h of operation of the first Large Volume Detector tower. The measured angular distribution of muon intensity has been converted to the ``depth--vertical-intensity'' relation in the depth range from 3 to 12 km w.e. The analysis of this relation allowed us to derive the power index $\ensuremath{\gamma}$ of the primary all-nucleon spectrum: $\ensuremath{\gamma}=2.78\ifmmode\pm\else\textpm\fi{}0.05.$ The ``depth--vertical-intensity'' relation has been converted to standard rock and the comparison with the data of other experiments has been done. We also present the derived vertical muon spectrum at sea level.