ATMOSPHERIC MUONS AND NEUTRINOS FROM CHARM

We have updated our previous investigation of the production of muons and neutrinos in cosmic ray interactions with the atmosphere, taking a ccount of recent results from the ep collider HERA in our QCD-based mo del for hadronic interactions. Qualitatively, our previous results rem ain unmodified: our predictions for the conventional muon and neutrino fluxes agree with earlier calculations, whereas the charm particle tr eatment we use gives significantly lower prompt fluxes compared to ear lier estimates. This implies better prospects for detecting very high energy neutrinos from cosmic sources.