Atmospheric neutrino flux and muon data

We present a new one-dimensional calculation of low and intermediate energy atmospheric muon and neutrino fluxes, using up-to-date data on primary cosmic rays and hadronic interactions. The existing agreement between calculated muon fluxes and the data of the CAPRICE 94 muon experiment provides an evidence in favor of the validity of our description of hadronic interactions and shower development. This also supports our neutrino fluxes which are essentially lower than those used for the standard analyses of the sub-GeV and multi-GeV neutrino induced events in underground detectors.