1 Searches for Particle Dark Matter - status Jan Conrad Oskar Klein Centre Physics Department Stockholm University Gamma 2012 July 9-13, 2012 Heidelberg

2 Who has never heard of this? 25 % 70%

3 Weakly Interacting Massive Particles (WIMPs) The weak interaction mass scale and ordinary gauge couplings give right relic DM density without fine-tuning. Mass scale O(GeV)-O(TeV), makes them Cold Dark Matter Will not talk about axions 1, WISPs (sub-eV), sterile neutrinos (keV) Jungman+, Phys. Rept. (1996)

4 Detection of Dark Matter Indirect detection rate = (particle physics part) × (astrophysical part) X-sectionYield WIMP mass DM density

5 Universal signatures Y(E)   Z, Ullio et al. Phys.Rev.D66:123502,2002 Bringmann et al. JHEP 0801:049,2008. Birkedal et al.,   ...       

6 APP- halo density profile R. Catena Cosmological N-body simulations: Navarro- Frenk-White Einasto  ”Cuspy” Stellar dynamics: e.g. Burkert.  ”Cored” Strongest signal from the Galactic Center ! We are here

7 APP- ´substructure

8 Targets and publications (incomplete) Fermi-LAT: TeVPA 2009, arXiv: Fermi: Goodenough & Hooper, arXiv: Fermi: Dobler et al., arXiv: Fermi-LAT: Phys. Rev. Lett. 107, (2011) H.E.S.S.: Astropart.Phys. 34 (2011) MAGIC: Astrophys.J. 697 (2009) VERITAS: Astrophys.J. 720 (2010) VERITAS: Phys.Rev.D85:062001,2012 Fermi-LAT: Phys.Rev.Lett.104:091302,2010 Fermi: Vertongen et al. JCAP 1105 (2011) 027 Fermi: Weniger et al. arXiv: Fermi: Bringmann et al. arXiv: Fermi-LAT: , Phys.Rev.D. HESS: see v. Eldik talk later today Fermi-LAT: JCAP 1004:014,2010 Fermi: Akorvazian et. al.arXiv: Fermi : Huetsi et. al. arXiv: H.E.S.S. Phys.Rev.Lett. 106 (2011) Fermi: Cirelli et. al. arXIv: Fermi-LAT: arXiv: Galactic Centre Dwarf galaxies and Galaxy Clusters Galactic Halo Extra Galactic Lines

9 Targets - comments Galactic Centre Dwarf galaxies and Galaxy Clusters Galactic Halo Extra Galactic Lines Strongest signal expected, most difficult background Hard sources, not well understood diffuse emission Dwarfs: weak signal, but relatively well controlled Dark Matter Distribution and essentially no background (if at high latitude). Clusters: DM density not well constrained, but provides boost factor (extended emission), so good for discovery (if lucky) Fermi-LAT: spatial and spectral discrimination, good statititstics, extreme freedom in galactic diffuse emission. IACT: best potential, small systematics due to diffuse emission, ~100 hour observation time (GC halo) Very model dependent, good as target for spatial analysis. Smoking gun*, got to get lucky.

10 Dwarfs galaxies – cleanest target DM dominated (M/L ~ ). Nearby (~ 100 kpc) Low background but relatively small signal Stellar velocities can be used to measure DM density (error can be propagated to particle constraints) e.g: Charbonnier+, MNRAS 418 (2011) 1526 Strigari+,Phys. Rev. D, 75, Evans+, Phys. Rev., D69, , (2004)

11 Dwarf galaxies probed in gamma-rays H.E.S.S.MAGICFermi Veritas

12 Analysis details Exposure (hours) Background modeling DM distribution Fermi 11 month, 24 month (~ 1500 h) Diffuse/ Point sources Empirical NFW H.E.S.S.~15On-off Empirical NFW Theo. NFW VERITAS ~15 ~50 (Segue) On-off Empirical NFW Empirical Einasto MAGIC~15On-offEmpir. NFW Empir. core/cusp Kazantzidis

13 The Fermi-LAT dwarf analysis (maximum likelihood) Two new methodological approaches: Combining single source likelihoods  less sensitive to individual source fluctuations, improved constraints, but analysis can be optimized individually 1) Including uncertainties in DM density Applied to a the combination  over-all result is much less affected by the DM density uncertainties (impact reduced by factor 10).

14 Dwarf constraints -status χχ  qq

15 Large signal (shape and spectrum)  Large background  Very complicated background for the Fermi-LAT Galactic diffuse emission: Best shot for Air Cherenkov telescopes However see: Fermi-LAT: arXiv:

16 H.E.S.S. Galactic Center Halo Galactic center is observed anyway 112 hours of GC observations Little diffuse background, sensitive to gradients “only” 16 Signal BG 5 deg Abramowski et al, PRL 106 (2011) LAT Draco 11 month

17 Gamma-ray constraints, present status χχ  qq

18 Future: Cherenkov Telescope Array Right now: optimization of array configuration DM targets studied in upcoming paper: – Galactic Centre Halo – Dwarf Galaxies – Clusters of Galaxies – Spatial signal/Axions … under review by Astroparticle Physics, to appear very soon …

19 Gamma-ray constraints – with CTA Doro+ (CTA Consort), Astroparticle Physics. On CTA: see W. Hofmann tomorrow.

20 CTA DMA FERMI Gamma-ray flux Direct detection cross section (pb) Present- day limit Some LHC detectable Complementarity (Direct/Indirect) Gamma-rays Direct detection, neutrinos (Sun) Bringmann+, Phys.Rev. D83 (2011) Next generation limit pMSSM

21 Complementarity with LHC Bertone+,Phys.Rev. D85 (2012) LHC solution: DM LHC solution: NOT DM Gaugino masses Excluded with Fermi- LAT dwarf limit Empty contours: LHC only Filled: Including Fermi dSph Result pMSSM (benchmark from coannihilation region)

22 ”Detections” From Bergström, Ann.Phys. (Berlin) 524, (2012) ~ GeV WIMPs ~ TeV WIMPs ~ MeV WIMPs

23 A line in Fermi-LAT data? 3.3σ trial corrected (~50 events) 5σ trial corrected Su&Finkbeiner, arXiv: Bringmann+, arXiv: Weniger arXiv: Weniger x- sec Fermi-LAT (2 year), arXiv: also:Boyarski+, arXiv: Tempel+, arXiv: (4.5σ)

24 Questions to be answered before booking the trip to Stockholm Is it instrumental, a fluke or physics? – What is the (sufficiently strong) line signal in the Fermi-LAT Earth Limb emission (ZENITH>60, 0 < THETA< 60), at the same energy? – Can a GC hard source in connection with point spread function modelling cause this effect? If it is physics, is it dark matter? – Why do Su+Finkbeiner find an offset? – Can it be a non-line spectral feature? – Can other physical processes except DM produce the feature? Aharonian+, arXiv: Profumo+, arXiv: Future interesting high resolution instruments: GAMMA-400 (2018), DAMPE (China) (2015), large area instrument HESS II, (see Weniger’s talk later today).

25 Final remarks and summary Most robust gamma-ray searches ….. – Dwarf spheroidal galaxies: Fermi-LAT – Galactic Center halo (H.E.S.S.). Gamma-ray searches have constrained the benchmark cross- section of ~ cm -3 s, for WIMPs < 30 GeV, with a robust and clean method. … at the same time yielding ”indications” worth to explore experimentally (not quite theoretically yet) …. Orthogonality to direct/neutrinos and LHC in the most commonly studied theoretical scenarios (Supersymmetry). – acc: LHC results, direct: Xenon 1t, IceCube results..

26 Future In 2019: CTA/Fermi-LAT constrain thermal WIMP x-sec from 10 GeV – 10 TeV.  Endgame for the WIMP? … unless of course we get lucky … – nature picks a model with large line cross-section  Galactic Centre New players: Gamma-400 (2018), DAMPE (2015), HESSII ? – nature introduces large enough substructure boost in clusters of galaxies  Galactic clusters

27 Backup

28 Summary of line emission constraints EGRET: Pullen at al, Phys.Rev.D76:063006,2007 H.E.S.S: Ripken, PhD thesis, Hamburg U. EGRET GC (binned) Fermi HESS GC (binned) 100 h U X 1 lines IDM lines Mambrini, JCAP 0912:005,2009 Gustafsson et al, PRL,99:041301,2007 MSSM Weniger line

29 ATLAS mono-jet results

30 Apropos LHC … what about the Higgs? no general statements possible.... well, what is it? (spin 0, couplings to other particles ~ mass), consistent with SM Higgs or not? – Large gamma-gamma decay rate might indicate a contribution from BSM particles Implication studied in certain contexts of SUSY: – mSUGRA: implies rather small direct detection x-sec  detectable by Xenon-1t If line indication correct: annihilation with Higgs  Dirac Dark Matter Buckley+, arXiv: Akula+, arXiv: