Event Rates vs Cross Sections

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Event Rates vs Cross Sections
at
Neutrino Telescopes
August 29, 2006
Shahid Hussain University of Delaware
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down neutrinos
Look at the upward case in more detail .
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EVent rates
A simple model

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Solve (analytically)
volume-detector with d0
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How does the simple model compare with a
detailed simulation? Let's do a detailed
numerical simulation using ICECUBE as an
example....
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SIMULATION

• Neutrino propagation through the Earth Solve
  the coupled Boltzmann equations for three
  neutrino flavors and the tau lepton, keeping the
  following details
• Calculate neutrino-nucleon, deeply inelastic,
  cross sections (differential and total).
• Include regeneration/down scattering terms.
• 3. Use variable density model of the Earth.
• 4. Include tau decays and tau energy losses.
• 5. Volume detector at depth d0, 1.9km.
• Finally, as an example, calculate shower,
  muon, and tau event rates, as a function of the
  neutrino nucleon cross sections, for ICECUBE
  using WB flux model.

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We simulate three possibilities for
cross-section scaling CASE I CASE
II CASE III
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SUMMARY

• For a given neutrino telescope, the scaling of
  event rates with neutrino-nucleon cross-sections
  depends on the event type, neutrino energy, and
  cross-section model.

• Details are important
• 1. Detector depth Above a 100PeV, even a 2km
  detector depth may cause a significant loss in
  event rates at cross-sections larger than the SM
  value.
• 2. Cross-section inelasticity Significant
  differences in event rates for cross-section
  models with different inelasticities.

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• For energies around 1-10 PeV, within a decade of
  change in cross-section
• Downward rates
• showers leptons
• Upward rates
• showers
• leptons ( ,
  )

surface
volume
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• As an example, for the model 610-8
  (GeV.cm2.s)-1 (E(GeV))-2, simulation for
  ICECUBE gives (upward rates/yr) in the SM
• For the bin 3.16-10PeV
• showers0.7 muons0.8 taus 0.2, 0.1
• Rates integrated above a PeV
• showers2.4 muons2.2 taus 0.9, 0.3