Gary C. Hill, CCAPP Symposium 2009, Ohio State University, October 12th, 2009 Photograph: Forest...

Gary C. Hill, CCAPP Symposium 2009 , Ohio State University, October 12th, 2009Gary C. Hill, CCAPP Symposium 2009 , Ohio State University, October 12th, 2009

The search for extra-terrestrial The search for extra-terrestrial sources of high energy neutrinos sources of high energy neutrinos

with IceCubewith IceCube

Photograph: Forest Banks

Gary C. HillGary C. HillUniversity of Wisconsin, MadisonUniversity of Wisconsin, Madison

for the IceCube collaborationfor the IceCube collaboration


cosmic rayscosmic rays charged - badcharged - bad

gamma raysgamma rays neutral - goodneutral - good absorbed - badabsorbed - bad

neutrinosneutrinos neutral - goodneutral - good not absorbed -not absorbed - good and bad!good and bad!

It’s a mysterious universe!It’s a mysterious universe!

Messenger particles forMessenger particles forhigh energy astronomy:high energy astronomy:


Neutrino and gamma production Neutrino and gamma production in cosmic ray accelerators?in cosmic ray accelerators?

ee

0, ppp

ee

Hadronic accelerator? – Hadronic accelerator? – cosmic ray origin?cosmic ray origin?

The TeV gammas?The TeV gammas?

Let’s look for Let’s look for these neutrinos!these neutrinos!

-rays-rays fromfromsynchrotronsynchrotron


Cosmic ray induced Cosmic ray induced “guaranteed sources”“guaranteed sources”

ee

0, ppp

ee

Cosmic rays on CosmicCosmic rays on CosmicMicrowave Background:Microwave Background: GZK neutrinosGZK neutrinos EHE: 10EHE: 109-109-10 GeV GeV

Cosmic rays on the earth’s atmosphere:Cosmic rays on the earth’s atmosphere:Atmospheric neutrinos Atmospheric neutrinos

Cosmic rays onCosmic rays ongalactic plane:galactic plane:galactic planegalactic planeneutrinosneutrinos


The high-energy neutrino skyThe high-energy neutrino sky


Atmospheric Atmospheric NeutrinosNeutrinos

Cosmic Ray

≈15 Km

π+

+

e+

e

pions, kaons and charmpions, kaons and charm


XeNe

XN

backgroundbackgroundatmosphericatmosphericmuonmuon

Direction:Direction:Reconstruction ofReconstruction ofCerenkov coneCerenkov coneEnergy:Energy:Counting of modulesCounting of modulesthat see photonsthat see photons


Event Signatures in IceCubeEvent Signatures in IceCube

signature signature

1013 eV (10 TeV)~90 hits

6x1015 eV (6 PeV)~1000 hits

Multi-PeV

+N+...

± (300 m!)

+hadrons

AMANDAAMANDA

Expect about 100,000 events/yr


Where are we pointing?Where are we pointing?


Moon declination during first 15 yearsMoon declination during first 15 years


RA distribution relative to moonRA distribution relative to moon


Li and Ma significance distributionLi and Ma significance distribution


Point source searchesPoint source searches


IC40 6 month all-sky point source searchIC40 6 month all-sky point source search


pre-trial significance 10-4.4

expected in 61% of random skies

IC40 6 month all-sky point source searchIC40 6 month all-sky point source search


Search for a diffuse Search for a diffuse signal with IC40 signal with IC40

Diffuse modelsDiffuse modelsall harder (~Eall harder (~E-2-2) than) thanatmospheric (~Eatmospheric (~E-3.7-3.7):):energy separationenergy separationNch variableNch variable

Range of Range of spectral slopes:spectral slopes:start with Estart with E-2-2


Blind regionBlind region

Energy separation:Energy separation:Nch variableNch variableBlind analysis: Blind analysis: Best limit setting powerBest limit setting power(model rejection potential)(model rejection potential)Nch>100Nch>100 E-2 test flux

Atmospheric neutrinos


Sensitivity:Sensitivity:for bg=6.1 eventsfor bg=6.1 eventsmedian event limit 5.84median event limit 5.84Flux limit : 5.84/66.7x10Flux limit : 5.84/66.7x10-6-6

= 8.8 x 10= 8.8 x 10-8-8


Unblind the data:Unblind the data:6 events observed6 events observedevent limit 5.84event limit 5.84Flux limit : 5.84/66.1x10Flux limit : 5.84/66.1x10-6-6

= 8.8 x 10= 8.8 x 10-8-8


Reconstructing The Muon energy lossReconstructing The Muon energy loss

Approximate as:

loglog}){|}({log1

NnnPk

iiiii

dust

ycl

ean

deep

shallow

Incorporate Ice Properties:

Formulate LLH:e+e-

pair-creation

bremsstrahlung

photo-nuclear


Energy estimator comparisonEnergy estimator comparison

Reconstructed dE/dX Number of Channels


Atmospheric neutrinos

E-2 test flux


Likelihood shape analysis - probability Likelihood shape analysis - probability of observable shape distribution {nof observable shape distribution {n i i } }

given theory {given theory {μμii}} ? ?

Product of Poisson probabilities over bins:

)(

1 !

)()})({|}({

i

i

en

nPk

i i

ni

ii

},...,,,...,, 12 kmm 1{

m parameters of interest; k-m nuisance parameters

Gary Hill


Atmospheric neutrinos onlyAtmospheric neutrinos only


Allowed EAllowed E-2-2 and prompt contributions and prompt contributions

Number of E-2

Nu

mb

er o

f p

rom

pt


Atmospheric and EAtmospheric and E-2 -2 neutrinosneutrinos



Number of E-2

Nu

mb

er o

f p

rom

pt


Atmospheric, EAtmospheric, E-2 -2 and prompt neutrinos and prompt neutrinos



Number of E-2

Nu

mb

er o

f p

rom

pt


IC40 diffuse sensitivityIC40 diffuse sensitivity

Gary C. Hill, CCAPP Symposium 2009, Ohio State University, October 12th, 2009 Photograph: Forest...

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