Secondary decays in atmospheric charm contributions to the flux of muons and muon neutrinos

Abstract We present a calculation of the fluxes of muons and muon neutrinos from the decays of pions and kaons that are themselves the decay products of charmed particles produced in the atmosphere by cosmic ray-air collisions. Using the perturbative cross section for charm production, these lepton fluxes are two to three orders of magnitude smaller than the fluxes from the decays of pions and kaons directly produced in cosmic ray-air collisions. Intrinsic charm models do not significantly alter our conclusions for E 3 GeV. Models with a charm cross section enhanced in the region above an incident cosmic ray energy of 10 3 GeV give enhanced lepton fluxes above 10 4 GeV, a region in which prompt muons dominate over the secondary decay contributions.