ATMOSPHERIC MUON FLUX AT SEA-LEVEL, UNDERGROUND, AND UNDERWATER - ART. NO. 054001

The vertical sea-level muon spectrum at energies above 1 GeV and the m uon intensities at depths up to 18 km w.e. in different rocks and in w ater are calculated. The results are particularly collated with a grea t body of the ground-level, underground, and underwater muon data. In the hadron-cascade calculations, we take into account the logarithmic growth with energy of inelastic cross sections and pion, kaon, and nuc leon generation in pion-nucleus collisions. For evaluating the prompt- muon contribution to the muon flux, we apply the two phenomenological approaches to the charm production problem: the recombination quark-pa rton model and the quark-gluon string model. To solve the muon transpo rt equation at large depths of a homogeneous medium, we used a semiana lytical method, which allows the inclusion of an arbitrary (decreasing ) muon spectrum at the medium boundary and real energy dependence of b oth continuous and discrete muon energy losses. The method is checked for accuracy by direct Monte Carlo calculation. Whenever possible, we give simple fitting formulas describing our numerical results. [S0556- 2821(98)00313-0].