2006/6/212006/6/21 11
IceCube EHE analysisIceCube EHE analysisOur findings and roadmap to analysisOur findings and roadmap to analysis
Shigeru YoshidaShigeru YoshidaFor the EHE working groupFor the EHE working group
2006/6/212006/6/21 22
DOM response to high NPEsDOM response to high NPEs
Log
10 (A
TW
D e
stim
ated
NP
E)
Estimated number of photo-electrons per DOM
ATWD or FADC?
Log
10 (F
AD
C b
ased
est
imat
ed N
PE
)
Log10 (ATWD based estimated NPE)
L
og10
(FA
DC
est
imat
ed N
PE
)
Log10 (MC Truth NPE) Log10 (MC Truth NPE)
Red: DOM of which ATWD charge is largerBlue: DOM FADC is larger
Npe saturation Npe saturation
“EHE specific” response!
2006/6/212006/6/21 33
NPE Energy DistributionNPE Energy Distribution
E-1 fluxes
containedcontained
GZK Atmospheric GZK
107 1010 [GeV] 107 1010 [GeV] 107 1010 [GeV]
Log
Np
e
2006/6/212006/6/21 44
NPE DistributionNPE Distribution
Distribution Distribution difference difference between the between the signals and signals and background! background!
GZKGZK
Atmospheric
2006/6/212006/6/21 55
Zenith Angle DistributionZenith Angle Distribution
Signals peak at Signals peak at horizontal horizontal directiondirection
Background Background distribute over distribute over down-going down-going regionregion
GZKGZK
Atmospheric
up down
2006/6/212006/6/21 66
Preliminary Event SelectionPreliminary Event Selection
GZK Atmospheric GZK
2006/6/212006/6/21 77
Event Rate with completed Event Rate with completed detectordetector
GZK 0.35 events/year
GZK 0.31 events/year
Atmospheric 0.033 events/year
GZKGZK
Atmospheric
GZKGZK
Atmospheric
GZK: S. Yoshida et. al. (1997) ApJ 479:547 (m=4, Zmax=4)
IceCube Preliminary
2006/6/212006/6/21 88
GZK Signal
Roadmap to analysisRoadmap to analysisAtmospheric BG
Standard CandleIn-Ice data9-strings unblinded data
Energy
Npe
Log(
Npe
)
NDOM
Cos(
zeni
th)
Log(Npe)
Cos(
zeni
th)
Log(Npe)
IceSim IceSim
))cos(,(
Ef
dE
dN
Tune
Energy
Eff.
Area
Extrapolate to signal domain
Empirical Model
2006/6/212006/6/21 99
9-strings working data9-strings working data
Npe>104Npe>104
NDOM >80NDOM >80
2006/6/212006/6/21 1010
9-strings working data9-strings working data
Npe>104
~ 500Events/yr
Needs statistics ! to understandIntensity(Npe, zenith), DOM response in EHE regime
2006/6/212006/6/21 1111
Muon bundlesMuon bundles1PeV bundle of 1000 muons (1TeV/muon)• Npe only would not be able to resolve tracks
• We do not know cosmic ray intensity in EHE
• We do not know cosmic ray composition in EHE
• Corsika has not reconstructed AGASA/Auger data9-strings “EHE” REAL DATA
Log(Npe)
Cos(
zeni
th)
Build Empirical Model
IceSim
))cos(,(
ENf
dE
dNm
2006/6/212006/6/21 1212
Why no problem in unblinding?Why no problem in unblinding?Signal stats in the following data is by far large.Almost independent confirmation!!
Expect
ed E
vent
Rate
[/y
ear]
This Year
Y2007
Y2008
x 2
x 1.5
2006/6/212006/6/21 1313
Why no problem in unblinding?Why no problem in unblinding?Background and Signals are so different inEnergies (Npe’s) and cos(1st-guess zenith)
This cut? This cut?Or this cut? Or this cut?
2006/6/212006/6/21 1414
Sensitivity/Bound Sensitivity/Bound Quasi-differential Quasi-differential methodmethod
S. Yoshida et. al. (2004)Phys. Rev. D 69 103004
Bound: energy dependent!!
][/3.2)( )( nobservatioevent TEdLogE
dJN
This is MODEL independent!!
2006/6/212006/6/21 1515
Beyond Npe and First-guessBeyond Npe and First-guessEnergy/Geometry recoEnergy/Geometry reco
e
NnNnP
Nn
k
i i
i
ii
i
!!!}){|}({
1
Waveform-based likelihood(proposed by Gary)
Utilize unscattered photon hits? (suggested by Lutz in 2004)
Including morenon-contained events
Log(Npe) Log(Energy)
cos(
1st g
uess
)
cos
(reco
)
2006/6/212006/6/21 1616
Our Bread and ButterOur Bread and Butter
Photo by David Boersma
Introducing “Yoshida” bottle(s)Your WG wins them if you publish your results earlier than anybody else!
