Recent Results & Status

of IceCube

Dark 2009

Christchurch, NZ

Jan. 18 - 24, 2009

Seon-Hee Seo

(Stockholm Univ.)

for IceCube Collaboration

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

2

Outline

! Introduction

! The IceCube Detector

! Recent Results

! Current Status

! Future: Deep Core

! Conclusion

Science cover: 2007

Vol. 315, issue 5818

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

3

We would like to answer:

-- What are the sources?

-- What's the physics at/near the sources?

At earth we observe:

-- Cosmic rays (~80% protons)

-- Photons

-- Neutrinos

Crab

Nature-produced High E Particles

---

4

Detecting Astrophysical Particles

IceCube

• Photons get absorbed (or pair-production) above 50 TeV.

• Protons get bent below 10 EeV and strongly attenuated above

50 EeV (GZK cut-off).

• Neutrinos cover all energy range, point back, but hard to detect.

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

5

Neutrino Telescope

Requirements:

-- Large detection volume to compensate for small cross section and

small flux of neutrinos

-- Optically transparent medium: water, ice

Detectors:

-- Water: DUMAND, Baikal, ANTARES, NESTOR, NEMO, KM3Net

-- Ice: AMANDA, IceCube (successor of AMANDA)

Water

Ice

Location

Northern

Southern

Deployment

Mostly year-round

austral summer

PMT noise rate

~ 40 KHz

~0.5 KHz

Scattering length

> 100 m @466nm

~ 20 m @ 400 nm

Absorption length

~ 60 m @466 nm

~110 m @ 400 nm

Detector geometry

Unstable

Stable

Medium

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

6

The IceCube Collaboration

Bartol Research Institute, Delaware

Pennsylvania State University

UC Irvine

Clark-Atlanta University

University of Maryland

University of Wisconsin-Madison

University of Wisconsin-River Falls

Lawrence Berkeley National Lab.

Southern University and A&M

University of Alaska, Anchorage

Georgia Tech University

Stockholm University

Belgium (4):

Université Libre de

Vrije Universiteit Brussel

Germany (7):

Universität Mainz

DESY-Zeuthen

Universität Dortmund

Universität Wuppertal

Humboldt Universität

Japan (1):

New Zealand (1):

Netherlands

Utrecht University

Switzerland

EPFL, Lausanne

~250

members

33

institutions

9

countries

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

7

~1 Km

Summer: ~240 people

Winter: ~50 people

IceCube

New Station

South Pole

AMANDA II

Skyway

Amundsen-Scott South Pole Station

Antarctica

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Dark09, Christchurch,

New Zealand

8

The IceCube Detector

IceTop (air shower array):

80 stations

2 frozen-water tanks / station

2 DOMs / tank

InIce:

80 strings

60 DOMs / string

17 m vertical spacing

125 m between strings

~1km

-1450m

-2450m

InIce

AMANDA: 1996 - 2008

19 strings

677 OMs total

10-20 m vertical spacing

~40 m between strings

I’ll get back to

this later.

Deep Core

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

speed: ~90m/hr

9

Hot-water drilling

Hose reel

Drill tower

5 MW Hot

water

generator

String Deployment

Drilling to 2500 m < 40h

String deployment ~ 12h

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

10

Absorption

Bubbles

dust

Average optical parameters:

λ

abs

~ 110 m @ 400 nm

λ

sca

~ 20 m @ 400 nm

Ice Properties

At bottom half of detector (very clear ice):

λ

abs

~ 220 m, λ

sca

~ 40 m @ 400 nm

Ice

Ice

---

Digital Optical Module (DOM)

PMT base

LED flasher

main board

Housed in

33 cm Benthosphere

PMT

Hamamatsu R7081-02

(10”, 10-stage, 10

7

gain)

- Time-stamp at the DOM

- Capture complex waveforms at PMT

anode with Analog Transient Waveform

Digitizer (ATWD) & fADC

Digitized waveform

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

12

Neutrino Detection

Method: detect Cherenkov light from secondary particles produced

by neutrino interaction

CC

,ν

τ

,ν

τ

CC

Track

Cascade

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

13

Time resolution

~ 3 nsec

5 ~ 7 nsec

~ 50%

~ 50%

E resolution

log

10

(E/GeV)

2

o

~ 3

o

< 1

o

Angular resolution

IceCube-80

AMANDA

Track

Time resolution

~ 3 nsec

5 ~ 7 nsec

~ 20%

~ 20%

E resolution

log

10

(E/GeV)

Cascade

Angular resolution

---

---

ν Detection Quality

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

14

Data Transfer

-- Satellite: ~32.5 GB/day (Y2008), (pre-scaled) filtered events

-- Ship: once a year for all filtered events in tapes

Event Rates

2011

IC80

10 years

TBD

~ 200/day 1650 Hz

2008

IC40

~ 1year

1400 Hz

1000 Hz

2007

IC22

319 days

670 Hz

~ 20/day

550 Hz

2006

IC9

137 days

150 Hz

~ 1.5/day

80 Hz

2005

IC1

-

-

2

-

CR μ

Rate

Trigger

ν rate

Rate

Run

Length

Year

#Strings

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

15

Backgrounds

Up (N)

cos(zenith)

Down (S)

Coincident muons

simulation

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

16

IceCube Physics Reach

Astronomy/Astrophysics:

-- point source search: GRB, AGN, etc...

-- diffuse search

Cosmic ray physics:

-- compositions, energy spectrum

HEP:

-- neutrino oscillations over cosmologically long baseline

-- atmospheric neutrino oscillations

-- charm production from high energy atmospheric neutrinos

-- etc…

New physics:

--

WIMPs

, (GUT) monopoles, nuclearites, Q-balls, stau pairs

-- violation of Lorentz invariance, etc…

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

17

AMANDA Sky Map

significance

-- 3.8 years livetime data of AMANDA

-- Max. significance is 3.38σ

-- However, 95% of randomized data sets showed

significance of 3.38σ or greater.

Max. significance

3.38σ

δ=54

o

, α=11.4h

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

18

Location: Ra: 153.375° , Dec: 11.375°

Estimated pre-trial significance (p-value): -log10(p): 6.13995

p-value of post-trials: ~1.34%

IceCube 22 string Sky Map

275.7 live days

Preliminary

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19

Astrophysical ν Diffuse Flux Limit

AMANDA 3.8 yr limit

: 10

-11

~ 10

-10

E

2

dΦ/dE (TeVcm

-2

s

-1

)

Expected IceCube80 (1 yr) sensitivity: 10

-12

~ 10

-11

E

2

dΦ/dE (TeVcm

-2

s

-1

)

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

20

Atmospheric ν

-- atmospheric ν are

irreducible BG.

-- AMANDA measurement

is similar to the two

 

popular

atm. ν models.

Preliminary

SuperK data,

González-García, Maltoni, & Rojo,

JHEP 0610 (2006) 075

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

21

Super Nova Monitoring

d

e

t

e

c

t

i

o

n

r

a

d

i

u

s

AMANDA

IceCube

30 kpc

- AMANDA sees 90% of the galaxy

- IceCube will see out to the LMC

(Large Magellanic Cloud, ~50 kpc)

0

5

10 sec

Count rates

(IceCube)

Rate increase

O(10cm) long tracks

on top of dark noise

Bursts of low-energy (MeV) neutrinos

from core collapse supernovae

The produced positron is emitted almost

isotropically

ν

e

+ p → n + e

+

SNEWS (SuperNova Early Warning System)

is a collaborative effort among Super-K, SNO,

LVD, KamLAND, AMANDA, BooNE and

gravitational wave experiments

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

22

IceCube WIMP Search: Indirect

Earth

preliminary

-- No excess was

observed w/ 22 strings.

-- We set 90% CL on the

muon flux from Sun.

-- We also set current best

limit on SD x-section.

looking for excess ν

μ

in the Sun direction

See A. Rizzo’s talk!

90% CL

Preliminary

---

Sub-relativistic Monopoles

m

M

>= ~10

16

GeV (GUT)

M +

p

→

M +

e

+

+ π

0

(2γ)

→

em shower

-- catalysis of nucleon decay by GUT

magnetic monopoles (σ

= ~ 10

-56

cm

2

)

-- baryon & lepton number violation

Rubakov-Callan mechanism:

or 2

typical

strong int. x-section

suppression factor

(smaller for higher Z atom & lower β)

=

0

n

!

F

("),

n

=1

"

#

#

!

0

=

F

(! )=

(for β < 10

-3

)

AMANDA 2001 (64 live days)

preliminary

2

0.18

0

!

"

"=

!

nucl

"

" =

0

Nucleon

velocity

~ 0.1

Hydrogen:

Oxygen:

*** We also have preliminary flux limits on

relativistic monopole search

w/ AMANDA.

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24

Violation of Lorentz Invariance

Violation of Lorentz Invariance (VLI):

-- one of the aspects in quantum gravity

-- natural in Planck scale (~10

19

GeV)

-- but also feasible in much lower energy

-- can be tested in, for example,

(A) neutrino oscilation (different from mass osc.):

different osc. prob. (velocity eigen state),

no ν mass dependence but L/E

(B) observing higher UHE ν flux than that of WB bound:

E

thresh

for ν interactions can be modified by VLI

Living Rev. Relativity

, 8, 5

c - δ

1

ν

c - δ

2

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IceCube Talk

Seo, Stockholm Univ.

25

VLI Preliminary Result

--- AMANDA data (3.8 live years) showed

no evidence

for ν osc. Induced by VLI

--- δc/c < 2.8 × 10

-27

(90%CL) with

P

νμ

-->

νμ

(maximal mixing)

cf. SuperK + K2K limit: δc/c < 1.9 × 10

-27

(90%CL)

90%, CL

Excluded

IceCube 10 yr. 90% sensitivity

SuperK + K2K

90% contour

95%, CL

99%, CL

90%, CL

preliminary

ξ: VLI mixing angle

in 2 flavor system

Δδ = δc/c

Maximal

mixing

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Dark09, Christchurch,

New Zealand

AMANDA

IceCube string deployed

12/05 – 01/06

IceCube string

deployed 01/05

IceCube string and

IceTop station deployed

12/06 – 01/07

IceCube Lab

commissioned

Deployed 15+1 strings in 2008/09

IceCube string deployed

12/07 – 01/08

IceCube Deployment Status

Y2011: completion

21

30

29

40

50

39

38

49

59

46

47

48

58

57

66

67

74

65

73

78

56

72

(98% DOMs are

fully functional.)

In 2008, 40 strings (50%) taking

physics data

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

27

Future: Deep Core

•

To improve

low E event

efficiency

-- indirect DM search, atm. ν osc, etc..

•

total 6 strings (75 m apart)

cf. nominal strings: 125 m apart

•

60 DOMs/string

--

high QE DOMs

(~ 35% more light yield)

-- DOMs are densely spaced

•

4

π

detector:

-- veto surrounding bottom inner

core (6 DC + 7 IC)

-- explore southern sky as well as

Galactic Center

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

28

ν Effective Area Comparison

ν effective area increased by deep core in low E region

Preliminary

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

29

Conclusion

• IceCube has been taking data smoothly w/ > 50% detector:

100% detector is expected in 2011.

• We have very interesting results with IceCube 22 strings and

complete AMANDA 7 years data, which will be published soon.

• However we have no evidence for a source of

extra-terrestrial neutrinos yet.

• IceCube deep core will play a critical role in low E physics

including indirect Dark Matter search.

• Future extensions optimized for EHE neutrinos are being

considered.

---

Swedish ice breaker

LC-130 Hercules landing at SPole

IceCube Counting House

Myself

Thank you!

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

31

Backup slides

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

32

Search for ν from GRB

Time window search:

--- search around GRB duration (T

90

):

this reduces BG significantly.

--- use GRB trigger info from other exp. (BATSE, Swift, Fermi, etc…)

Rolling search:

--- scan through all the data in a given year and search for a

statistically significant signal within a fixed time duration.

(T

90

)

---

33

ν Flux Limits from GRB

Cascade

(Trig & Roll)

Cascade

(Rolling)

ν

μ

search

All flavor limits by AMANDA

WB03

WB03

MN06

MN06

R03b

R03b

R03a

R03a

--R03b:

Supranova model

--WB03:

Waxman-Bahcall model

--R03a:

Choked Burst model

--MN06:

Murase Nagataki model

ν

μ

search:

Over 400 Northern

Hemisphere GRBs

Cascade search

Trigger search

with 73 GRBs

Rolling seach

for 2001-2003

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

34

-- Relativistic monopoles will leave

very bright track in ice medium:

~ 8300 x muon

(g

2

= [n*e/(2

∗α)]

2

= ∼8300

e

2

for n

= 1.33

)

-- Slowly moving (down to β ~ 0.5)

monopoles can be detected via

δ electrons generated along the

monopole path.

-- IceCube will be large improvement

● Bigger effective area

-- IceCube will push limit towards

~10

-19

cm

-2

s

-1

sr

(Preliminary sensitivity)

Relativistic Monopoles

Preliminary

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Dark09, Christchurch,

New Zealand

IceCube Talk

Seo, Stockholm Univ.

35

GUT Magnetic Monopole

• grand unification core

– virtual X-bosons (10

-29

cm)

• electroweak unification

– virtual W, Z, γ, g (10

-16

cm)

• confinement region

– g, γ (10

-13

cm)

• condensate

– fermion-antifermion pairs

(r ~ m

f

-1

)