GZK EHE detection

What is the GZK mechanism?

EHE Propagation in the Earth

Expected intensities at the IceCube depth

Atmospheric – background

Event rate

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GZK Neutrino ProductionGZK Neutrino Production

2.725 K

411 photons / cm3

Gamma Beam Energy (GeV)

Cro

ss S

ect

ion (mb)

0.1

0.01

γ + p→Δ （1232）→ π o p or π + n

Gamma Beam Energy (GeV)

Cro

ss S

ect

ion (mb)

0.1

0.01

γ + p→Δ （1232）→ π o p or π + n

Gamma Beam Energy (GeV)

Cro

ss S

ect

ion (mb)

0.1

0.01

γ + p→Δ （1232）→ π o p or π + n

0.6 x 10-27 cm2

γp

n p

π＋ μ＋ ν

e＋

νγ

E = 10 20 eV

E 0.8 x 10 20 eV ~

Conventional Mechanism of EHE neutrinos!!Conventional Mechanism of EHE neutrinos!!　　

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Yoshida and Teshima 1993Yoshida, Dai, Jui, Sommers 1997

Note: The oscillations convert e, to e,,

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/ propagation in Earth

e

e

e/

e/

Weak

Weak

Weak

Inco

min

gProducts

Weak

Weak

Weak

Cascades

Cascades

Decay DecayWeak

Pair/decayBremss Pair Pair PhotoNucl.

PhotoNucl.DecayPair Pair

PairBremssDecay

DecayWeak

Decay

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Tau(Neutrinos) from

Suppression

By decay

Muon(Neutrinos) from

Nadir Angle

１．４ｋｍ

１ｋｍ

Upward

Ice

Rock ν

±πγ

ν

+e －e１ｋｍ

Downward

ν

γ

γ

+e －e

lepton

lepton

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Upward-going Downward going!!

Atmospheric muon! – a major backgrondBut so steep spectrum

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Down-going events dominates…

1400 m

2800 m

11000mUp Down

Atmospheric is strongly attenuated…

Flux as a function of energy deposit in km3

dE/dX~E E~XbE

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Up Down

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Intensity of EHE and GZK m=4 Zmax=4

I(E>10PeV) I(E>10PeV) RATE [/yr/km2]

Down 5.90 10-19 5.97 10-19 0.37

Up 3.91 10-20 6.63 10-20 0.03

I(E>10PeV) Energy Deposit

I(E>10PeV) Energy Deposit

Down 4.75 10-19 2.94 10-19 0.24

m=7 Zmax=5Down

7.21 10-17 4.83 10-17 37.9

Atm 1.74 10-19 0.05

[cm-2 sec-1]

Eµ=10 TeV ≈ 90 hits Eµ=6 PeV ≈ 1000 hits

How EHE events look like

The typical light cylinder generated by a muon of 100 GeV is 20 m, 1PeV 400 m, 1EeV it is about 600 to 700 m.

TAUP 2003Conclusion

appeared in 10 PeV- EeV are our prime target on GZK detection.

1/100-1/500 of primary intensity!Downward and make main contributions in PeV -EeV

Energy Estimation would be a key for the bg reductionBecause atmospheric spectrum ~ E-3.7

GZK is DETECTABLE by IceCube 0.2-40 events/year (BG 0.05 events/year)

IceCube has great capability for TeV-PeV-induced muons taking advantage of long rangein the clear ice.

For EHE like the GZK….