Prompt muon contribution to the flux underwater

We present high energy spectra and zenith-angle distributions of the atmospheric muons computed for the depths of the locations of the underwater neutrino telescopes. We compare the calculations with the data obtained in the Baikal and the AMANDA muon experiments. The prompt muon contribution to the muon flux underwater due to recent perturbative QCD-based models of the charm production is expected to be observable at the depths of the large underwater neutrino telescopes. This appears to be probable even at rather shallow depths (1–2 km), provided the energy threshold for muon detection is raised above $\sim 100\hspace{0.5em}\mathrm{TeV}.$