IceCube
High-energy Neutrino Astrophysics
Where we are and where we go

Shigeru Yoshida
Department of Physics
Chiba University2007-2008:
18 Strings

2006-2007:
13 Strings

2008・2009 Data
40 strings
80 IceTop tank

IceCube2009-2010
59 strings
2010-2011
79 strings

2005-2006: 8 Strings

1450m

2004-2005 : 1 String
80+6 Strings
60 Optical Modules
17 m between Modules
125 m between Strings
2450m

The IceCube Collaboration
Germany:

Sweden:USA:
Bartol Research Institute, Delaware
University of California, Berkeley
University of California, Irvine
Pennsylvania State University
Clark‐Atlanta University
Ohio State University
Georgia Tech
University of MarylandUniversity of Alabama, Tuscaloosa
University of Wisconsin‐Madison
University of Wisconsin‐River Falls
Lawrence Berkeley National Lab.
University of Kansas
Southern University and A&M
College, Baton Rouge
University of Alaska, Anchorage

Uppsala Universitet
Stockholm Universitet

UK:
Oxford University

Switzerland:
EPFL

DESY‐Zeuthen
Universität Mainz
Universität Dortmund
Universität Wuppertal
Humboldt Universität
MPI Heidelberg
RWTH Aachen

Belgium:
Université Libre de Bruxelles
Vrije Universiteit Brussel
Universiteit Gent
Université de Mons‐HainautJapan:
Chiba University

New Zealand:
University of Canterbury

33 institutions, ~250 members
http://icecube.wisc.edu

DOMDigital Optical Module
HV Base“Flasher Board”
Main Board(DOM-MB)
10” PMT13” Glass(hemi)sphereData Filtering at South PolePY 2008 season
40 strings ~ a half of the completed IceCube

Simple Majority Trigger
8 folds with 5 μ sec

Muon Filter

EHE Filter

selects“up-going” tracks

selects“bright” events~20 Hz~1.3 Hz~ 950 Hz

Cascade Filter

Many others“cascade”-like events Min Bias
Moon
IceTop~17 Hzetc

NPE > 630 p.e.

To Northern Hemisphereselects

Point Source SearchMaterials to cookνμ Æ μ baseμ filtered, EHE filtered and min-bias events

Require Quality cuts in multiple stages

Common aspects
In many other analysis

Point source specificto filter out vastly dominateddown-going muons
to realize reasonable agreement
between MC and data
to create a sample of eventswith good angular resolution

ν skymap
up-going μ’s w/ atmospheric ν BG

down-going PeV μ’s w/ cosmic-rays BG

All sky search: post-trial p-value 18%
Hottest spot: RA 113.75 Dec 15.15 -log(p)=5.28
Jon Dumm (UW-Madison)

Source List Resultsp-valueCrab--BL Lac
0.226
Mrk 5010.421
Mrk 4210.142
M87--CygA
0.439
PKS 1622-297 0.048

IceCube Preliminary

The highest significancefrom list of the 39 IceCube sources

Pretrial 4.8 % Æpost-trial 62 % for the source list

* Shown here is only a part of the IceCube pre-determined source list

Jon Dumm (UW-Madison)

Point Source Sensitivity
IceCube Preliminary

Jon Dumm (UW-Madison)

Stacking Searches
p-value

Milagro Sources (17 sources)
9 TeV SNRs + 8 new associated with Fermi(6 SNRs with Fermi association)

32 %1% (a posteriori)

Nearby starburst galaxies (127 sources)

33 %Clusters of glaxies (5 sources)

78 %Followed Murase, Inoue, Nagataki (2008)
Virgo, Perseus, Centaurus, Coma, Ophiuchus

Jon Dumm (UW-Madison)

GRB model-dependent SearchMaterials to cook
μ filtered and EHE filteredνμ Æ μ baseRequire Quality cuts in multiple stages

Common aspects
In many other analysis

GRB specificto filter out vastly dominateddown-going muonsZenith > 85 deg.

to realize reasonable agreement
between MC and data
use “off-time” data as the BG sample
to train the BDT

Building of the PDFs
Unbinned Maximum Likelihood
PDF
Total PDF.
Time PDF

Predicted ν spectra
Guetta et al Astropart.Phys. 20 (2004) 429

Optimize BDT scoreto maximize the discovery
potential

No association of ν’s
with GRB..
109 GRBs detected by Fermi, Swift, Konus, and WAM
in the IceCube FOV (2009 June – 2010 May)

Peter Redl (UMD)

We are on the way to indicate GRBs areunlikely to be a major UHECR origin.

GZKνSearchO(PeV) ~ 10 EeV
Materials to cook
EHE filtered events

All ν flavor baseNo strong quality cuts necessary because..

Unique featuresin this particular analysis

these ν’s are more energetic thanatmospheric μ BG
Just increase energy thresholdin analysis leads to better S/NGZK analysis specific issues• Earth filters out signal ν as well

GZK ν search
Energy Dist. @ IceCube Depth

Detection Principle

Zenith Dist. @ IceCube Depth

Yoshida et al PRD 2004

through-going track

Secondary μ and τ from νÆ Sensitive tostarting track/ cascadeνμ ντ

Directly induced events from νÆ Sensitive toνe νμ ντAnd tracks arrive horizontally

The detailed description available inAbbasi et al PRD 82 072003 (2010)

GZK ν search
Detection Principle
EnergyÆ NPE (total # of photoelectrons)

Look for luminous (high NPE)
horizontal events

Experimental verification
MC overestimates
NPE by ~18%

Sys. error~ 7% in SIG rate
~ 50% in BG rate

DataMCGZK ν search
Final level 3 cut
Selects bright(=high NPE) events penetrating long path from the earth surface
GZK MC (νe + νμ + ντ)Atmospheric μ MC

Obs. dataShallow
Keep

KeepCutCut

higher energy ÆKeepCut

higher energy Æhigher energy ÆDeep
CutCut Keep

Final BG 0.107 +/- 0.015 (stat.)
GZK
0.573 +/- 0.005 (stat.)+0.065- 0.103 (sys)+0.080 (sys)- 0.066

Keep

Aya Ishihara (Chiba)Upper limits in EHE

Aya Ishihara (Chiba)

E2 φ(E) < 4.2x10-8 GeV/cm2 sec sr (2PeV < E < 8 EeV)All flavor (νe + νμ + ντ) limits
Systematic errors included

IceCube PreliminaryConstraints on Ultra-high energy
cosmic ray emission
Now IceCube : constrained UHECR cosmological luminosity
at the comparable level with Fermi, but more direct way

A major fraction of the Fermi
diffuse γ is NOT responsiblefor UHECR emissions

IceCuberejected0.4 events expectedby I3 2008 runslerAhet

1020sy.phartpostral A

The Highest NPE event

KeepCutThis event
p-value for the background hypothesis ~0.2%(posteriori)

Aya Ishihara (Chiba)• Detected in 2008 December 10th
• NPE 2.55x105 photo-electrons• Zenith 64.7 deg

The Highest NPE event~ 10 PeV if background~ 100 PeV if (GZK) νIceCube baseline Sensitivity
The same analysis method/systematics applied on the full IceCube MC
IC40~2009/5~2012/5

Aya Ishihara (Chiba)

Expected # of EHE signal events
IC40# of events(333days)

ModelsIC80(full)# of events(3 years, by 2012/5)

GZK1 (Yoshida et al)

0.57

3.1

GZK2 Strong Evol. (Sigl)

0.91

4.9

GZK3 (ESS with WL=0.0)

0.29

1.5

GZK4 (ESS with WL=0.7)

0.47

2.5

GZK5 (Ahlers max)

0.89

4.8

GZK6 (Ahlers best fit)

0.43

2.3

Z-Burst1.03

5.1

Top Down(SUSY)5.68

31.6

Top Down(QCD)

1.19

6.3

W&B(evol)

3.7

24.5

W&B(no evol)

1.1

5.5