IceCube Galactic Halo Analysis

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IceCube Galactic Halo Analysis Carsten Rott Jan-Patrick Huelss CCAPP Mini Workshop Columbus OH August 6, 2009 145 0 m 2450 m August 6, 2009 1 CCAPP DM Miniworkshop

description

IceCube Galactic Halo Analysis . Carsten Rott Jan-Patrick Huelss CCAPP Mini Workshop Columbus OH August 6, 2009. 1450 m. 2450 m. IceCube Detector and DeepCore. E reco = 500 TeV. 1450 m. Dust concentration. 2450 m. Very clear ice. General Detector Capabilities. - PowerPoint PPT Presentation

Transcript of IceCube Galactic Halo Analysis

Page 1: IceCube Galactic Halo Analysis

CCAPP DM Miniworkshop 1

IceCube Galactic Halo Analysis

Carsten Rott Jan-Patrick Huelss

CCAPP Mini WorkshopColumbus OH

August 6, 2009

1450 m

2450 m

August 6, 2009

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1450 m

2450 mVeryclearice

Dust concentration

Ereco= 500 TeV

IceCube Detector and DeepCore

August 6, 2009

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General Detector Capabilities

Muon from IC40 Data

Tracks Cascades

Track-Like IceCube AMANDATime Resolution 2 ns 5-7 ns

Energy Resolution (log10E)

0.3 – 0.4 0.3 – 0.4

Field of View 2π 2π

Noise Rate low

Angular resolution <1o ~1.5-2.5o

Cascade-Like IceCube AMANDATime Resolution 2 ns 5-7 ns

Energy Resolution (log10E)

0.18 0.18

Field of View 4π 4π

Noise Rate low

Angular resolution 30o ~30-40o

IceCube Angular Resolution < 1°

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Dark Matter Searches

Solar Earth HaloNeutrino Flux, Scattering

cross-sectionNeutrino Flux, ? Neutrino Flux, Self-

annihilation cross-section

Muon neutrinos Muon neutrinos Muon neutrinos, Cascades

Background off-source on-source

Background simulations Background off-source on-source

Excess Excess Anisotropy, Spectrum

IceCube ( + Deep Core) IceCube ( + Deep Core) DeepCore ( + IceCube)

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Annihilation rate ∝r 2

Galactic Center on Southern hemisphere -30o

-Requires identification of down-going starting events

Neutrino signal “least detectable”, hence allows to set conservative limit on the total self-annihilation cross-section

[Yuksel, Horiuchi, Beacom, Ando (2007)]

Halo WIMPs

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Galactic center: cos(y)=1 (B=0,L=0)

Example: 10 degree zenith angle band mapped in galactic coordinates

[L=0,B=0]RA(f)

q

DfDf

A neutrino flux from annihilations in the Milky way halo might be observable as neutrino flux anisotropy.Use up-going tracks (from the Northern hemisphere) to have access to TeV range neutrinos.

Preliminary

Halo WIMPs

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Preliminary

What to look for ?

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• Deep Core Strings 6 strings with high quantum

efficiency PMTs, densely spaced 7 “standard” IceCube strings

located in best ice (below 2100 m exceptionally clear)

Interstring spacing 72m Uses high Quantum Efficiency PMTs,

that have about 40% higher efficiency Located in the deep ice Lower atmospheric muon

background Larger scattering length ~40m

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Deep Core Extension

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arXiv:0810.3698

99

Fermi

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Effective Area

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ConclusionsIceCube DarkMatter Halo Analysis underway using

Northern Hemisphere with 22 string datasetAccess to Southern Hemisphere with IceCube 40 and

DeepCore will significantly improve sensitivityIceCube Neutrino Effective Area not so different from

Fermi

Conclusions

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Motivation

gap

Spin-dependent WIMP-proton cross-section

Spin-dependent WIMP-nucleon cross-section very difficult to access in direct detection experiments

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Search for an excess neutrino flux from the direction of the sunAnalysis performed with the IceCube 22 string detector and 104 days of livetime (when the sun below the horizon)

Solar WIMPs

Cold Dark Matter candidate particle is assumed to be the LSP (neutralino) in MSSM, R-parity conserving scenarioNeutralino is a Majorana particle and self-annihilatesConsider two annihilation channels:

– Hard: cc → W+ W–→ n n

– Soft: cc→ bb → n nConsider 7 neutralino masses from 50 GeV to 5 TeV

Solar WIMPscc

Preliminary

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(for equilibrium):

July 8, 2009 Carsten Rott - ICRC09 Lodz 13

Solar capture rate:

)07.0()1(~ HeSI

HSI

HSD

locallocalC v

C r

CA C21

Cross-section Limits

WIMP Annihilation Rate:

c

nm

nm

or

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• Look for an excess of (muon) neutrinos in the direction of the sun

• No evidence for a signal observed• Upper limits on muon flux from neutralino

annihilations in the Sun

• Under the assumption of equilibrium condition in the Sun, a limit on the WIMP-Nucleon cross-section can be obtained

• For spin-dependent couplings, IceCube’s sensitivity is about 2-orders of magnitude better than direct searches arXiv: 0902.2460 (PRL 102, 201302)

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Solar WIMPs

Preliminary

Preliminary

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Solar WIMPs (AMANDA Limits and Future Prospects)

Preliminary

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• AMANDA analysis on-going• IceCube analysis on-going

• Understanding of low energy vertical tracks extremely important

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Earth WIMPs Dark Matter could be clustered in the

centre of the Earth

Annihilation signal might be

observable in vertically up-going

events

Earth WIMPs

Energy and zenith angle of muon neutrino events in the signal region

(see also “Search for Atmospheric Oscillations with IceCube”)

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nm

String Trigger:5 DOMs hit within a series of 7 DOMs within a time window of 1500ns

Preliminary

Earth WIMPs

Beginning with 40 string data, IceCube lowered the multiplicity 8 trigger threshold to 5 applying a string trigger

Preliminary

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Spin Independent Result

• Under the assumption of equilibrium condition in the Sun (and the assumption that capture is dominated by spin-independent cross-section), a limit on the WIMP-Nucleon cross-section can be obtained

• IceCube limits are competitive with direct detection experiments at WIMP masses, where IceCube is sensitive

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New stringent limit on the WIMP-nucleon scattering cross-section using IceCube 22-string data

DeepCore combined with IceCube will allow to probe a large region of SUSY parameter space that is difficult to access in direct detection experiments

Preliminary

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IceCube Detector StatusSeason Deployed2004-2005 1 string

2005-2006 8 strings

2006-2007 13 strings

2007-2008 18 strings

2008-2009 18+1 strings

04/05

05/06

06/0707/08

08/09

09/10

10/11

IC40

IC22

IC22IC40

DeepCore

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Systematic uncertainties on the effective volume:• Neutrino oscillation: 4%• Neutrino-nucleon cross-section: 3%• Muon propagation in ice: <1%• Proton propagation & absolute OM sensitivity: 17-24%• Spread in OM sensitivity: <5%• Time & position calibration: <5%• Signal MC statistics: 3-5%Total systematic uncertainty: 19-26%

Preliminary

Solar WIMP analysis