1 research outputs found
Shower Power: Isolating the Prompt Atmospheric Neutrino Flux Using Electron Neutrinos
At high energies, the very steep decrease of the conventional atmospheric
component of the neutrino spectrum should allow the emergence of even small and
isotropic components of the total spectrum, indicative of new physics, provided
that they are less steeply decreasing, as generically expected. One candidate
is the prompt atmospheric neutrino flux, a probe of cosmic ray composition in
the region of the knee as well as small- QCD, below the reach of collider
experiments. A second is the diffuse extragalactic background due to distant
and unresolved AGNs and GRBs, a key test of the nature of the highest-energy
sources in the universe. Separating these new physics components from the
conventional atmospheric neutrino flux, as well as from each other, will be
very challenging. We show that the charged-current {\it electron} neutrino
"shower" channel should be particularly effective for isolating the prompt
atmospheric neutrino flux, and that it is more generally an important
complement to the usually-considered charged-current {\it muon} neutrino
"track" channel. These conclusions remain true even for the low prompt
atmospheric neutrino flux predicted in a realistic cosmic ray scenario with
heavy and varying composition across the knee (Candia and Roulet, 2003 JCAP
{\bf 0309}, 005). We also improve the corresponding calculation of the neutrino
flux induced by cosmic ray collisions with the interstellar medium.Comment: 15 pages, 4 figures. Minor modifications, version accepted for
publication in JCA