Detecting neutrinos from AGN: New fluxes and cross sections

Abstract

New information on the structure of the nucleon from the HERA ep collider leads to higher neutrino cross sections for the processes ν µ (ν µ ) + N → µ − (µ + ) + 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.

Determination of the atmospheric neutrino flux and searches for new physics with AMANDA-II

“…For the input atmospheric muon neutrino spectrum, we generate an isotropic powerlaw flux with the NUSIM neutrino simulator [40] and then reweight the events to standard flux predictions [11,41]. We have extended the predicted fluxes to the TeV energy range by fitting the low-energy region with the Gaisser parametrization [42] and then extrapolating above 700 GeV.…”

Neutrino interactions at ultrahigh energies

“…The reactions (ν ℓ ,ν ℓ )N → (ℓ − , ℓ + ) + anything and (ν ℓ ,ν ℓ )N → (ν ℓ ,ν ℓ ) + anything are the major sources of both the desired signal and the attenuation of the neutrino "beam" as it passes through the Earth en route to the detector. Through the past dozen years, improving knowledge of the partonic structure of the nucleon has made possible a series of increasingly refined predictions for the interaction cross sections [5][6][7][8][9][10][11][12][13]. Over the same period, ideas about the flux of neutrinos from active galactic nuclei (AGNs) and other extraterrestrial sources have evolved considerably.…”

Probing the structure of jet-driven core-collapse supernova and long gamma-ray burst progenitors with high-energy neutrinos

“…To obtain HEN interaction lengths, we adopt the neutrino cross sections obtained by Gandhi et al [66] (other calculations give similar results; see, e.g., [68]). We additionally take into account nuclear effects (i.e.…”