  New information on the structure of the nucleon from the HERA ep collider
leads to higher neutrino cross sections for the processes nu_mu + N --> mu + X
needed to calculate the expected rates of astrophysical neutrino induced muons
in large detectors either under construction, or in the design stage. These
higher cross sections lead to higher muon rates for arrival angles where
neutrino attenuation in the earth is less important. On the other hand, new
estimates of AGN neutrino fluxes suggest that the expected muon rates in these
detectors may be much lower than previously calculated. I use the new cross
sections to calculate the expected muon rates and angular distributions in
large detectors for a variety of AGN models and compare these rates with the
atmospheric neutrino backrounds (from both conventional decay channels and the
"prompt" charmed meson decay channels). If the lowest flux estimates are
correct, there may be diffculties in determining the origin of a small excess
of muons, due to the large uncertainty in the rate of the charmed meson
neutrino production channel. However, the more optimistic AGN neutrino fluxes
should be detectable in proposed detectors, such as DUMAND-II, AMANDA, NESTOR
and Lake Baikal.

Astrophysics