SEARCHES FOR ANNIHILATING DARK MATTER IN THE MILKY WAY HALO WITH - - PowerPoint PPT Presentation

SEARCHES FOR ANNIHILATING DARK MATTER IN THE MILKY WAY HALO WITH ICECUBE

Samuel Flis*, Morten Medici, Martin Wolf for the IceCube Collaboration

ICRC 2017, 12-20 July, Busan, South Korea

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

T A R G E T E D S I G N A L F R O M M I L K Y W A Y H A L O

• Signal depends on the assumed

halo profjle

T A R G E T E D S I G N A L F R O M M I L K Y W A Y H A L O

• Signal depends on the assumed

halo profjle

• Spectra are model dependent

dark matter dark matter b,W,τ → ν b,W,τ → ν Indirect detection

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

N E U T R I N O P H Y S I C S W I T H I C E C U B E

• 1 km3 instrumented ice below the

South Pole (fjnished 2010)

• 5160 light sensors to detect

Cherenkov radiation

• Measuring neutrino initiated

events

• Energies down to 10s GeV
• Two main event topologies:

track-like, cascade-like (shower)

• Stable operations and reliable

hardware (>99% uptime)

Neutrino

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

L A T E S T U P D A T E S O N A N A L Y S E S

• Covering dark matter masses from 10 GeV to

300 TeV

• Exploiting three difgerent event selections for

a specifjc class of events

IC 4yr PS + 3yr MESE (tracks) IC 2yr cascades IC 3yr GC tracks

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

S I G N A L A N D B A C K G R O U N D

• Background at trigger level
• atm. muons 10¹¹/year
• atm. neutrinos 10⁵/year
• Signal from Milky Way halo:
• Galactic Center: 29° above horizon
• Signal events <~1000/year

(from limits)

Cosmic rays IceCube Muon Neutrino

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

A N A L Y S I S T E C H N I Q U E

• Likelihood approach with a mixture of:
• Signal: Modeled from simulated neutrino

events weighted to represent annihilating dark matter in the Milky Way halo

• Background: Estimated from experimental

data

• Signal contamination in background

estimation is subtracted

• Same approach used in all presented analyses

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

A N A L Y S I S T E C H N I Q U E : S I G N A L S U B T R A C T I O N

Analysis techniques of DM halo searches in IceCube

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SAMUEL FLIS

• The assumption: is not

valid in general. ( = scrambled data)

A N A L Y S I S T E C H N I Q U E : S I G N A L S U B T R A C T I O N

• The assumption: is not

valid in general. ( = scrambled data)

• The scrambled data is instead

assumed to consist of background and scrambled signal

Analysis techniques of DM halo searches in IceCube

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SAMUEL FLIS

L O W E N E R G Y A N A L Y S I S

• Dark matter masses between 10-1000 GeV
• Using the fjnished IceCube with 86 strings
• Exploiting good pointing resolution of the muon

tracks

• Implementation of new event reconstruction

important below neutrino energies of 100s of GeV

• 3 years of data: 1007 days of livetime
• Results submitted and public

[arXiv:1705.08103]

IC 4yr PS + 3yr MESE IC 2yr cascades IC 3yr GC tracks

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

H I G H E N E R G Y T R A C K A N A L Y S I S

• Dark matter masses between 0.3-1000 TeV
• Using tracks from IceCube dataset designed for

point source searches (PS) consisting of 4 years of data

• Focus on galactic halo makes it less efgected by

the dark matter halo profjle assumptions

• Includes an IceCube dataset dedicated to the

southern hemisphere (MESE) consisting

• f three years of data
• Inclusion of energy in likelihood analysis

provides extra sensitivity above 10s TeV

IC 4yr PS + 3yr MESE IC 2yr cascades IC 3yr GC tracks

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

[IceCube Collaboration, M. G. Aartsen et al. Astrophys. J. 796 (2014) 109] [IceCube Collaboration, M. G. Aartsen et al., Astrophys. J. 824 (2016) L28]

H I G H E N E R G Y C A S C A D E A N A L Y S I S

• Dark matter masses between

3-300 TeV

• Exploiting the good energy

resolution from contained cascades

• Inclusion of energy provides extra

sensitivity

• Using an IceCube dataset designed for an

unfolding analysis of the neutrino spectrum

• Implementing a progressively smaller

fjducial volume for lower energy events

IC 4yr PS + 3yr MESE IC 2yr cascades IC 3yr GC tracks

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

[IceCube Collaboration, M. G. Aartsen et al., Phys. Rev. D 91 (2015) 022001]

R E S U L T S

• No excess above

expected background was

• bserved
• Limits were

calculated (here assuming a NFW profjle)

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

• No excess above

expected background was

• bserved
• Less gain from from

good pointing and central region for a cored profjle

R E S U L T S

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

S U M M A R Y

• No observation of a neutrino signal in IceCube

compatible with dark matter annihilation

• More sensitive analyses and longer reach in dark

matter masses provides very competitive limits

• n the annihilation cross section
• IceCube is less sensitive to the exact distribution
• f dark matter in the galactic halo.
• IceCube has better sensitivity to cored profjles

compared to other experiments

• There are more data to analyze!

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

Searching for DM in the Milky Way Halo with IceCube

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SAMUEL FLIS

Thank you for your attention!