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

2 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube 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

3 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube 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 Indirect detection dark b,W,τ → ν matter dark b,W,τ → ν matter

4 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube 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 km 3 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: Neutrino track-like, cascade-like (shower) ● Stable operations and reliable hardware (>99% uptime)

5 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube 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 3yr GC tracks IC 4yr PS + 3yr MESE (tracks) IC 2yr cascades

6 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube 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 Neutrino ● Signal from Milky Way halo: IceCube Muon ● Galactic Center: 29° above horizon ● Signal events <~1000/year (from limits) Cosmic rays

7 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube 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

8 SAMUEL FLIS Analysis techniques of DM halo searches in IceCube 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)

9 SAMUEL FLIS Analysis techniques of DM halo searches in IceCube 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

10 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube 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 IC 3yr GC tracks ● Results submitted and public IC 4yr PS + 3yr MESE [arXiv:1705.08103] IC 2yr cascades

11 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube 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 [IceCube Collaboration, M. G. Aartsen et al. Astrophys. J. 796 (2014) 109] ● 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 IC 3yr GC tracks of three years of data IC 4yr PS + 3yr MESE [IceCube Collaboration, M. G. Aartsen et al., Astrophys. J. 824 (2016) L28] ● Inclusion of energy in likelihood analysis IC 2yr cascades provides extra sensitivity above 10s TeV

12 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube 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 IC 3yr GC tracks spectrum IC 4yr PS + 3yr MESE [IceCube Collaboration, M. G. Aartsen et al., Phys. Rev. D 91 (2015) 022001] ● Implementing a progressively smaller IC 2yr cascades fjducial volume for lower energy events

13 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube R E S U L T S ● No excess above expected background was observed ● Limits were calculated (here assuming a NFW profjle)

14 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube R E S U L T S ● No excess above expected background was observed ● Less gain from from good pointing and central region for a cored profjle

15 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube 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 on the annihilation cross section ● IceCube is less sensitive to the exact distribution of dark matter in the galactic halo. ● IceCube has better sensitivity to cored profjles compared to other experiments ● There are more data to analyze!

16 SAMUEL FLIS Searching for DM in the Milky Way Halo with IceCube Thank you for your attention!