INDIRECT DARK MATTER SEARCHES IN ICECUBE WIN2017, UC IRVINE 2 DM - PowerPoint PPT Presentation

Photo: NSF/Hans Boenish MORTEN MEDICI INDIRECT DARK MATTER SEARCHES IN ICECUBE WIN2017, UC IRVINE

2 DM SEARCHES IN ICECUBE MORTEN MEDICI INDIRECT DETECTION WITH NEUTRINOS Indirect dark low concentration b, W, τ ν ’s matter ν dark b, W, τ ν ’s matter high concentration ν Stars: C. Beckett, S. Meneguolo, Royal Astronomical Society of Canada, 
 Milky Way: Trevor Jones, Earth: NASA

3 DM SEARCHES IN ICECUBE MORTEN MEDICI INDIRECT DETECTION WITH NEUTRINOS Indirect low concentration dark ν b, W, τ ν ’s matter dark b, W, τ ν ’s matter ν high concentration Stars: C. Beckett, S. Meneguolo, Royal Astronomical Society of Canada, 
 Milky Way: Trevor Jones, Sun: NOAA/CosmicQuest

4 DM SEARCHES IN ICECUBE MORTEN MEDICI NEUTRINO PHYSICS WITH ICECUBE ▸ 1 km 3 instrumented ice below 
 the South Pole (finished 2010) ▸ 5160 light sensors for detecting 
 Cherenkov radiation charged ▸ Measuring neutrino-initiated 
 particle events ▸ Energies down to 10s GeV ▸ Stable operation and reliable 
 hardware (> 99% livetime) neutrino

5 DM SEARCHES IN ICECUBE MORTEN MEDICI SIGNAL AND BACKGROUND cosmic rays ▸ Background at trigger level neutrino ▸ Atm. muons: 10 11 /year ▸ Atm. neutrinos: 10 5 /year IceCube ▸ Dark matter searches muon ▸ Sun: +/- 23 o above horizon ▸ Galactic center: 29 o above horizon

6 DM SEARCHES IN ICECUBE MORTEN MEDICI ICECUBE EVENTS ▸ Two topologies: ▸ Tracks (best pointing) ▸ Cascades (contain all energy) Science 342, (2013) ▸ Reconstruct neutrino: Charge, time, geometry Direction, energy, position

GALACTIC HALO

8 DM SEARCHES IN ICECUBE MORTEN MEDICI TARGETED SIGNAL FROM GALACTIC HALO ▸ Spectrum model dependent ▸ Signal sensitive to 
 assumed halo profile 10 1 b ¯ b τ + τ − 10 4 W + W − ν ¯ 10 0 ν 10 3 Density [ 10 7 M � / kpc 3 ] µ + µ − 10 − 1 10 2 dN/dE ν 10 − 2 10 1 10 0 10 − 3 10 � 1 Burkert 10 − 4 10 � 2 NFW Spectrum of ν µ 10 − 5 m DM = 100 GeV 10 � 3 10 � 2 10 � 1 10 0 10 1 10 2 10 − 6 Radius [kpc] 0 20 40 60 80 100 120 E ν [GeV]

DM SEARCHES IN ICECUBE MORTEN MEDICI ANALYSIS TECHNIQUE ▸ Likelihood approach with a mixture of: ▸ Signal : Modelled from simulated neutrino events weighted to correspond to dark matter annihilation ▸ Background : Estimated from exp. data ▸ Signal contamination in background is subtracted ▸ Same approach used across all presented galactic halo analyses

10 DM SEARCHES IN ICECUBE MORTEN MEDICI LATEST UPDATE ON ANALYSES ▸ Covering dark matter masses 
 from 10 GeV to 300 TeV ▸ Exploiting three different event selections, each optimised for a specific class of events IC 3yr GC tracks IC 4yr PS+3yr MESE IC 2yr cascades

11 DM SEARCHES IN ICECUBE MORTEN MEDICI LOW ENERGY ANALYSIS ▸ Dark matter masses between 10-1000 GeV ▸ Using the finished IceCube with 86 strings ▸ Exploiting good pointing resolution of the muon tracks ▸ Implementation of new event reconstruction important below neutrinos 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

12 DM SEARCHES IN ICECUBE MORTEN MEDICI HIGH ENERGY TRACK ANALYSIS ▸ Dark matter masses between 0.3-1000 TeV ▸ Using tracks from IceCube dataset designed for point 
 source searches (PS) ▸ Focus on galactic halo makes it less effected by the dark matter halo profile assumptions ▸ Includes an IceCube dataset dedicated to the southern hemisphere (MESE) IC 3yr GC tracks ▸ Inclusion of energy in likelihood analysis 
 IC 4yr PS+3yr MESE provides extra sensitivity above 10s TeV IC 2yr cascades

13 DM SEARCHES IN ICECUBE MORTEN MEDICI HIGH ENERGY CASCADE ANALYSIS ▸ Dark matter masses between 3-300 TeV ▸ Exploiting the good energy resolution from contained cascades ▸ Inclusion of energy provides extra sensitivity above 10s TeV ▸ Using an IceCube dataset designed for an unfolding analysis of the neutrino spectrum IC 3yr GC tracks ▸ Implementing a progressively larger veto 
 IC 4yr PS+3yr MESE for lower energy events IC 2yr cascades

14 DM SEARCHES IN ICECUBE MORTEN MEDICI GENERAL SUMMARY: GALACTIC HALO WIMPS ▸ No excess above the expected background was seen

15 DM SEARCHES IN ICECUBE MORTEN MEDICI GENERAL SUMMARY: GALACTIC HALO WIMPS ▸ Assuming Burkert dark matter halo profile

SOLAR SEARCH

17 DM SEARCHES IN ICECUBE MORTEN MEDICI TARGETED SIGNAL FROM THE SUN ▸ Accumulation of WIMP in the sun, assumed to 
 be in equilibrium with the annihilation rate

18 DM SEARCHES IN ICECUBE MORTEN MEDICI SOLAR WIMP STUDIES ▸ New results using the finished IceCube 
 with 86 strings ▸ Results published: 
 EPJC 77 146 (2017) [arXiv:1612.05949] ▸ 3 years of data: 532 days of livetime ▸ Two independent analyses focusing on high and low dark matter mass ▸ No excess above the expected background

19 DM SEARCHES IN ICECUBE MORTEN MEDICI SOLAR WIMP STUDIES ▸ Presents very competitive bounds on the 
 spin-dependent nucleon-dark matter interaction cross-section

20 DM SEARCHES IN ICECUBE MORTEN MEDICI SOLAR WIMP STUDIES ▸ pMSSM model scans, indicating the fraction of 
 hard and soft final states

DECAYING 
 DARK MATTER

22 DM SEARCHES IN ICECUBE MORTEN MEDICI DECAYING DARK MATTER STUDIES ▸ Dark matter signal: Galactic halo and isotropic extragalactic component ▸ Background: Atmospheric muons/neutrinos and astrophysical neutrinos ▸ Analysis fit: Dark matter mass / lifetime , isotropic astrophysical flux / index ▸ Two independent analyses using event selections designed for unfolding the neutrino spectrum: ▸ 1) Using dataset with 6 years of northern hemisphere tracks ▸ 2) Using dataset with 2 years of full sky cascades ▸ Focusing on the H ν - or Z ν -channel which has a significant peak in energy from the neutrino line spectrum ▸ No excess above the expected background

23 DM SEARCHES IN ICECUBE MORTEN MEDICI EXPERIMENTAL LIMITS ON DECAYING DARK MATTER ▸ Adding limits on dark matter lifetime for dark matter masses above 10 TeV for high mass dark matter

24 DM SEARCHES IN ICECUBE MORTEN MEDICI SUMMARY ▸ 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. ▸ Solar dark matter searches result in world strongest bound on the spin-dependent dark matter-nucleon interaction cross section

25 THANKS FOR YOUR ATTENTION!

26 DM SEARCHES IN ICECUBE MORTEN MEDICI SOLAR WIMP STUDIES ▸ Spin-independent dm-nucleon cross section

27 DM SEARCHES IN ICECUBE MORTEN MEDICI DECAYING DARK MATTER ▸ Significant excess of 
 high energy neutrinos 
 above backgrounds ▸ Used to look for decaying 
 heavy dark matter 1.0 PeV 1.1 PeV 2.0 PeV