Searches for Particle Dark Matter - status

1. Searches for Particle Dark Matter - status Jan Conrad Oskar Klein Centre Physics Department Stockholm University conrad@fysik.su.se • Gamma 2012 • July 9-13, 2012 • Heidelberg

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

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 Jungman+, Phys. Rept. (1996) Will not talk about axions1, WISPs (sub-eV), sterile neutrinos (keV)

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

5. Universal signatures Y(E) Ullio et al. Phys.Rev.D66:123502,2002 cc ...  p0  gg cc  Z,gg Birkedal et al., Bringmann et al. JHEP 0801:049,2008.

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

7. APP- ´substructure We are here

8. Targets and publications (incomplete) Galactic Centre Fermi-LAT: TeVPA 2009, arXiv:0912.3828  Fermi: Goodenough & Hooper, arXiv:0910.2998 Fermi: Dobler et al., arXiv:0910.4583 Dwarf galaxies and Galaxy Clusters Fermi-LAT: Phys. Rev. Lett. 107, 241302 (2011)H.E.S.S.: Astropart.Phys. 34 (2011) 608-616 MAGIC: Astrophys.J. 697 (2009) 1299-1304 VERITAS: Astrophys.J. 720 (2010) 1174-1180 . VERITAS: Phys.Rev.D85:062001,2012 H.E.S.S. Phys.Rev.Lett. 106 (2011) 161301 Fermi: Cirelli et. al. arXIv: 0912.0663 Fermi-LAT: arXiv: 1205.6474 Galactic Halo Fermi-LAT: JCAP 1004:014,2010 Fermi: Akorvazian et. al.arXiv:1002.3820 Fermi : Huetsi et. al. arXiv:1004.2036  Extra Galactic Fermi-LAT: Phys.Rev.Lett.104:091302,2010 Fermi: Vertongen et al. JCAP 1105 (2011) 027 Fermi: Weniger et al. arXiv:1204.2797  Fermi: Bringmann et al. arXiv:1203.1312 Fermi-LAT: 1205.2739, Phys.Rev.D. HESS: see v. Eldik talk later today Lines

9. Targets - comments Galactic Centre Strongest signal expected, most difficult background Hard sources, not well understood diffuse emission Dwarf galaxies and Galaxy Clusters 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) Galactic Halo 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) Extra Galactic Very model dependent, good as target for spatial analysis. Lines Smoking gun*, got to get lucky.

10. Dwarfs galaxies – cleanest target • DM dominated (M/L ~10--1000). • 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) 1526Strigari+,Phys. Rev. D, 75, 083526 Evans+, Phys. Rev., D69, 123501, (2004)

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

12. Analysis details

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. Galactic diffuse emission: Best shot for Air Cherenkov telescopes  Large signal (shape and spectrum)  Large background  Very complicated background for the Fermi-LAT However see: Fermi-LAT: arXiv: 1205.6474

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” BG Signal 5 deg Signal BG LAT Draco 11 month Abramowski et al, PRL 106 (2011) 161301 16

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. Complementarity (Direct/Indirect) CTA FERMI DMA Present-day limit Next generation limit pMSSM Direct detection, neutrinos (Sun) Direct detection cross section (pb) Some LHC detectable Gamma-ray flux Gamma-rays Bringmann+, Phys.Rev. D83 (2011) 045024

21. Complementarity with LHC pMSSM (benchmark from coannihilation region) Gaugino masses Excluded with Fermi-LAT dwarf limit LHC solution: NOT DM LHC solution: DM Empty contours: LHC only Filled: Including Fermi dSph Result Bertone+,Phys.Rev. D85 (2012) 055014

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

23. A line in Fermi-LAT data? Bringmann+, arXiv:1203.1312 Weniger arXiv:1204.2797 • 3.3σ trial corrected (~50 events) • 5σ trial corrected Su&Finkbeiner, arXiv:1206.1616 also:Boyarski+, arXiv:1205.4700 Tempel+, arXiv:1205.4882 (4.5σ) Weniger x-sec Fermi-LAT (2 year), arXiv:1205.2739

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? Profumo+, arXiv: 1204.6047 Aharonian+, arXiv:1207.0458 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 ~10-26 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 UX1 lines Mambrini, JCAP 0912:005,2009 Gustafsson et al, PRL,99:041301,2007 IDM lines Weniger line Fermi HESS GC (binned) 100 h MSSM EGRET GC (binned) EGRET: Pullen at al, Phys.Rev.D76:063006,2007 H.E.S.S: Ripken, PhD thesis, Hamburg U.

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:1207.1445 Akula+, arXiv:1207.1839