EHE Lepton Propagation in the EaEHE Lepton Propagation in the Earth and Its Implications to the Icerth and Its Implications to the Ice

CubeCube EHE EHE Propagation in the EarthPropagation in the Earth What is the GZK mechanism?What is the GZK mechanism? Expected intensities at the IceCube depthExpected intensities at the IceCube depth Atmospheric Atmospheric – background – background Event rateEvent rate IceCube EHE IceCube EHE sensitivitysensitivity

Mons 2003

Shigeru YoshidaChiba University

UHE (EeV or even higher) Neutrino EventsArriving Extremely Horizontally

• Needs Detailed Estimation• Limited Solid Angle Window

(NA)-1 ~ 600 (/10-32cm2) -1(/2.6g cm-3) -1 [km]

Involving the interactions generating electromagnetic/hadron cascades

N X e+e-

Mons 2003

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

DecayDecayDecay

Mons 2003

Tau(Neutrinos) from

Suppression

By decay

Muon(Neutrinos) from

Nadir Angle

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!!　　

Mons 2003

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

Mons 2003

Mons 2003

Upward-going Downward going!!

Atmospheric muon! – a major backgrondBut so steep spectrum

１．４ｋｍ

１ｋｍ

Downward

Upward

Ice

Rock

ν

ν

±π

γ

γ

γν

+e －e１ｋｍ

+e －e

lepton

lepton

EHE events!

Mons 2003

Down-going events dominate…

1400 m

2800 m

11000mUp Down

Atmospheric is attenuated faster…

Mons 2003

Flux as a function of energy Flux as a function of energy deposit in kmdeposit in km33

dE/dX~dE/dX~E E EE~~XbEXbE

Flux as a function of energy Flux as a function of energy deposit in kmdeposit in km33

dE/dX~dE/dX~E E EE~~XXEE

Mons 2003

Intensity of EHE Intensity of EHE and and

GZK GZK m=4m=4 ZZmaxmax=4=4

II(E>10PeV)(E>10PeV) II(E>10PeV)(E>10PeV) RATE RATE [/yr/[/yr/kmkm22]]

DownDown 5.90 105.90 10-19-19 5.97 105.97 10-19-19 0.370.37

UpUp 3.91 103.91 10-20-20 6.63 106.63 10-20-20 0.030.03

II(E>10PeV) (E>10PeV) Energy DepositEnergy Deposit

II(E>10PeV) (E>10PeV) Energy DepositEnergy Deposit

DownDown 4.75 104.75 10-19-19 3.28 103.28 10-19-19 0.250.25

m=7 Zm=7 Zmaxmax=5=5DownDown

7.21 107.21 10-17-17 4.83 104.83 10-17-17 37.937.9

Atm Atm 1.74 101.74 10-19-19 0.050.05

[cm-2 sec-1]

IceCube EHE IceCube EHE Sensitivity Sensitivity90% C.L. for 10 year observation

Mons 2003Conclusion

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

1/1000 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 0.3-40 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….

This Simulator is Open to the IceThis Simulator is Open to the IceCube Collaboration.Cube Collaboration.

JULIET JULIET ver1ver1((JJava-based ava-based UUltrahigh-energy ltrahigh-energy LLepton epton IIntnteegral gral TTrara

nsporter)nsporter) ee////////Propagator in rock/ice at EHEs (PPropagator in rock/ice at EHEs (P

eV or greater) by numerically calculating the treV or greater) by numerically calculating the transport equationsansport equations

ee////////Monte Carlo Event Generator (ignoMonte Carlo Event Generator (ignoring the ionization loss) from 100 TeV- 1ZeVring the ionization loss) from 100 TeV- 1ZeV

Downloadable from Downloadable from www-ppl.s.chiba-u.jp/research/IceCube/eheSim/www-ppl.s.chiba-u.jp/research/IceCube/eheSim/

Users Manual will be released within a few monUsers Manual will be released within a few monthsths

Backup slides Backup slides

IceCubeIceCube

1400 m

2400 m

AMANDA

South Pole

IceTop

Skiway

80 Strings80 Strings 4800 PMT 4800 PMT Instrumented volume: Instrumented volume:

1 km3 (1 Gt)1 km3 (1 Gt) IceCube is designed to IceCube is designed to

detect neutrinos of all fldetect neutrinos of all flavors at energies from avors at energies from 101077 eV (SN) to 10 eV (SN) to 102020 eV eV

Mons 2003

Cross Sections and the Energy Loss Term

CTEQ5 Parton Distribution for the evaluation

Mons 2003

１．４ｋｍ

１ｋｍ

Upward

Ice

Rock ν

±πγ

ν

+e －e１ｋｍ lepton

ν