Chiba, July 29, 2003 Tom Gaisser

Comments on atmospheric muon and neutrino backgrounds

in neutrino telescopes

Use semi-analytic estimates to display some systematic features of atmospheric muons and neutrinos deep underground

Chiba, July 29, 2003 Tom Gaisser

Muons at depth

From report of the Neutrino Facilities Assessment Committee

Chiba, July 29, 2003 Tom Gaisser

Muons at depth

(P. Desiati et al., ICRC2003)

From report of the Neutrino Facilities Assessment Committee

Chiba, July 29, 2003 Tom Gaisser

energy spectra at depth

See D Chirkin et al. for application to calibrating Nhit in AMANDA

Chiba, July 29, 2003 Tom Gaisser

Response functions for at depth

Fraction of multi-: .08, .05, ..03, .02, .01, .007 --decreases as depth increases

Chiba, July 29, 2003 Tom Gaisser

Muon multipliclity in coincident eventsArea--solid-angle ~ 1/3 km2sr (including angular dependence of EAS trigger)

Chiba, July 29, 2003 Tom Gaisser

Neutrino response

Neutrino energy Primary energy / nucleon

Chiba, July 29, 2003 Tom Gaisser

K/ bigger for than for Flavor-dependence of horizontal/vertical

Chiba, July 29, 2003 Tom Gaisser

Compare primary response of -induced to atmospheric

Response for atmospheric

Chiba, July 29, 2003 Tom Gaisser

Primary spectrum muons

Chiba, July 29, 2003 Tom Gaisser

Global atmospheric spectrum

Prompt

e

Solar

Plot shows sum ofneutrinos + antineutrinos

Slope = 3.7

Slope = 2.7

Chiba, July 29, 2003 Tom Gaisser

Summary

• Characteristic E ~ 200-300 GeV gives tag for energy calibration of neutrino telescope

• Response functions allow analysis of uncertainty from primary spectrum– -induced muon reponse independent of depth– response of atmospheric depends on depth– <10% multiple muons when triggering on deep

detector, but air shower trigger multi-mu