Search for Dark Matter with Ice Cube Catherine

Search for Dark Matter with Ice. Cube Catherine De Clercq for the Ice. Cube Collaboration Vrije Universiteit Brussel w 3. iihe. ac. be Dark Matter in LHC Era Kolkata 2011

Outline • Weakly Interacting Massive Particles as Cold Dark Matter • The Ice. Cube neutrino detector • Search for neutrino signals of WIMP annihilations in the Sun and near the Galactic Centre • Ice. Cube + Deep. Core : prospects for Dark Matter discovery in the coming years Catherine De Clercq DM in Ice. Cube 2

Evidence for Dark Matter from observations Indirect detection Dark matter Catherine De Clercq DM in Ice. Cube 3

Observations Gravitational lensing Galaxy rotation curves Begeman et al. 1991 Dark halo light gas Catherine De Clercq DM in Ice. Cube 4

WIMPs as cold Dark Matter • Weakly Interacting Massive Particles Bullet Cluster @ NASA • Non-relativistic at freeze-out • Mass [Ge. V-Te. V] • Can make up cold DM with observed abundance ≈ 0. 21 WMAP O(Weak interactions) Catherine De Clercq DM in Ice. Cube 5

Detection Catherine De Clercq DM in Ice. Cube 6

Indirect detection P IM W Catherine De Clercq IM P W e+ , γ DM in Ice. Cube , υ , p 7

Mission Instrument Neutrino detection Ice. Cube 8

Amundsen Scott South Pole Station Ice. Cube observatory Æ1 km At 1. 5 -2. 5 km depth Station Dark Matter in LHC Era Kolkata 2011 Skiway Control room

Ice. Cube Mission • search for extra-terrestrial neutrinos → natural accelerators producing HE cosmic rays • Such as Astronomischebron p ? ? – Active Galactic Nuclei – Gamma Ray Bursts – Super. Novae ? • Indirect Dark Matter search • Cosmic ray air showers with Ice. Top Catherine De Clercq DM in Ice. Cube 10

Ice. Cube detector Control room Ice. Top AMANDA -1450 m 1 km -2450 m Array of 80 strings with 60 Digital Optical Modules Catherine De Clercq DM in Ice. Cube 11

Ice. Cube detector Control room Ice. Top AMANDA -1450 m Deep. Core -2450 m Catherine De Clercq Deep. Core ØDenser spacing ØLow energy Ge. V-Te. V ØSouthern hemisphere DM in Ice. Cube 12

Neutrino detection & reconstruction • Record Cherenkov light pattern • Reconstruct muon track • Assume muon track aligned to neutrino path Ice. Cube Light sensors Muon track Charge Current interaction neutrino Catherine De Clercq DM in Ice. Cube 13

νµ Catherine De Clercq DM in Ice. Cube 14

Pointing resolution • Simulation : 1 Te. V muon → ΔΨ ≈ 1° • moon shadow observation → ΔΨ � 1. 25° – IC 40 (2008) 8 lunar months – 5σ deficit in atmospheric muon flux Ice. Cube preliminary - ICRC 2009 # events near moon Catherine De Clercq DM in Ice. Cube 15

Ice. Cube was completed on 18 December! (Nature. com) Giant, frozen neutrino telescope completed - December 18, 2010 Last optical module Science. Daily (Dec. 19, 2010) — Culminating a decade of planning, innovation and testing, construction of the world's largest neutrino observatory, installed in the ice of the Antarctic plateau at the geographic South Pole, was successfully completed December 18, 2010, New Zealand time. Catherine De Clercq DM in Ice. Cube 16

WIMP annihilations in the Sun WIMP annihilations near the Galactic Centre Search for dark matter Catherine De Clercq DM in Ice. Cube 17

Different strategies • Neutrinos from WIMP annihilations in the Sun: AMANDA, IC 22 • Neutrinos from WIMP annihilations in the galactic halo and near the galactic centre: IC 22, IC 40 • Neutrinos from WIMP annihilations in the centre of the Earth : work in progress

Data filtering Muon flux and WIMP annihilation rate WIMP-proton scattering cross section Solar WIMPs Catherine De Clercq DM in Ice. Cube 19

Solar WIMPs: detection principle rc c velocity distribution Earth Sun sscatt nμ n int. capture Detector annihilation m

signal and background BG A few 10’ 000 atmospheric neutrinos per year from northern hemisphere Max. a few neutrinos signal per year from WIMPs ~1010 atmospheric BG muons per year from southern hemisphere Catherine De Clercq DM in Ice. Cube 21

Data filtering • Muon tracks from νμ Charged Current interactions • When Sun below horizon: March-September • Nearly horizontal tracks Different levels of filtering 1 Te. V WIMP, hard channel selection efficiency 20% data Σ(atm BG) Atm µ+µµ AMANDA µ ν Atm. ν Ice. Cube Catherine De Clercq DM in Ice. Cube 22

Signal content from fit From off-source data Model dependent From MC simulations Neutralino 250 Ge. V to WW pr el im in ar y µ Data, AMANDA 812 d Background Best fit Catherine De Clercq DM in Ice. Cube 23

Search results AMANDA dedicated search M(WIMP) [50 -5000 Ge. V] Angular resolution 3 – 7 degrees 812 days livetime 2001 -06 Ice. Cube 22 strings dedicated search M(WIMP) [250 -5000 Ge. V] ≈ 3 degrees 104 days 2007 • No evidence for a signal in ~ 900 days livetime • → upper limits on neutralino annihilation rate in Sun & resulting muon flux Catherine De Clercq DM in Ice. Cube 24

Annihilation rate & muon flux experiment MSSM MC simulation sy u S rk a D neutralino annihilation rate Muon flux Catherine De Clercq DM in Ice. Cube 25

Neutralino models considered • Assume MSSM with R-parity conservation • Neutralino χ01 (LSP) is popular CDM candidate: weakly interacting, stable, massive • Consider 7 masses • and 2 annihilation channels • Simulation with WIMPSIM (Blennow & Edsjö JCAP 2008) Catherine De Clercq Dark Matter in AMANDA & Ice. Cube – IDM 2008 26

Muon flux from solar neutralinos AMANDA 01 -06 preliminary Super-K Desai (PRD 2004) Ice. Cube 2007 Abassi (PRL 2009) MSSM model predictions allowed by colliders & direct searches Catherine De Clercq DM in Ice. Cube 27

Scattering cross section • muon flux → scattering cross section • Assume – equilibrium between capture in Sun and annihilation – Spin-dependent scattering dominates capture in Sun • For given final state Wikström & Edsjö, JCAP 2009 Catherine De Clercq DM in Ice. Cube 28

Spin dependent scattering cross section Direct searches CDMS COUPP KIMS Super-K Desai (PRD 2004) AMANDA 01 -06 preliminary Ice. Cube 2007 Abassi (PRL 2009) MSSM model predictions allowed by colliders & direct searches Catherine De Clercq DM in Ice. Cube 29

LKP annihilations in the Sun • IC 22 data re-interpreted in model of Universal Extra Dimensions • KK-parity conserved → Lightest Kaluza Klein Particle γ(1) is DM candidate • similar observed muon energy spectra for neutralino & LKP 3 Te. V LKP γ(1) 250 Ge. V 3 Te. V χ0 Muon energy (Ge. V) Catherine De Clercq DM in Ice. Cube 30

LKP annihilations in the Sun Experiment – IC 22 angular distribution UED MC simulation LKP annihilation rate in Sun Dark. Susy Muon flux at Earth γ(1)p Scattering cross section Catherine De Clercq DM in Ice. Cube 31

LKP-proton SD cross section Ice. Cube 2007 Catherine De Clercq DM in Ice. Cube 32

Large scale anisotropy near Galactic Centre Dedicated GC search Self-annihilation cross section WIMPs in the halo Catherine De Clercq DM in Ice. Cube 33

Large scale neutrino anisotropy • Search for anisotropy near Galactic Centre in IC 22 point source sample • Background in ‘ON’ = BG in ‘OFF’ = atmospheric ν + µ Northern hemisphere = Ice. Cube ν field of view On-source 24 h Off-source 0 h

Large scale neutrino anisotropy • 5114 events in 276 days in 2007 • No anisotropy found Northern hemisphere = Ice. Cube ν field of view

Neutralino annihilation in the halo Halo models Catherine De Clercq DM in Ice. Cube 36

Limits on self-annihilation cross section • IC 22 anisotropy • NFW halo model • 4 annihilation channels Catherine De Clercq DM in Ice. Cube 37

Neutrinos from Galactic Centre • Search in IC 40 point source sample (2008) for excess in direction of Galactic Centre • ! Southern hemisphere : use few outer layers as veto against atmospheric muon background • No excess found in GC search bin veto region fiducial volume Catherine De Clercq DM in Ice. Cube 38

Limits • IC 22 anisotropy • IC 40 Galactic centre search • NFW halo model • 4 annihilation channels Catherine De Clercq DM in Ice. Cube 39

Ice. Cube + Deep. Core prospects Catherine De Clercq DM in Ice. Cube 40

Deep. Core and WIMPs • Deep. Core : low energy extension in deep clear ice • Use Ice. Cube as veto against downgoing atmospheric muons • Extend field of view to southern hemisphere in [10 Ge. V-few. Te. V] domain • Galactic Centre • year round solar WIMPs Catherine De Clercq DM in Ice. Cube 41

Muon flux from solar neutralinos AMANDA 01 -06 Ice. Cube 2007 Ice. Cube + Deep. Core 5 years sensitivity Catherine De Clercq DM in Ice. Cube 42

Neutralino scattering in Sun Ice. Cube 2007 AMANDA 01 -06 Ice. Cube + Deep. Core 5 years sensitivity Catherine De Clercq DM in Ice. Cube 43

Summary • Icecube/AMANDA data was used to search for indirect neutrino signal from WIMP annihilations in Sun & near Galactic Centre • No signal was found & upper limits were set on muon flux at Earth and Spin Dependent cross sections • Ice. Cube is completed and is largest ν detector in operation • Within 5 years sensitivity to DM signals will Ø improve by order of magnitude in [30 Ge. V-5 Te. V] Ø Unclude sources in Southern hemisphere Catherine De Clercq DM in Ice. Cube 44

Ice. Cube collaboration Icecube. wisc. edu Catherine De Clercq DM in Ice. Cube 45