Probing Dark Matter in Galaxy Clusters using Neutrinos

Transcription

1 Indirect Detection - Parallel Session I IDM 2012, Chicago Probing Dark Matter in Galaxy Clusters using Neutrinos In Collaboration with Ranjan Laha, arxiv/ PRD Basudeb Dasgupta CCAPP, Ohio State University

2 Dark Matter at All Scales DM Evidence CMB Universe DM Targets Local Group Earth/Sun Milky Way Structure Lensing MW Halo Solar System R o t a t i o n 1 mpc Curves Dwarfs 100 kpc 1 Mpc Clusters 1 Gpc Basudeb Dasgupta, IDM Chicago, 23 July

3 Neutrinos from DM Earth/Sun Freese (1986), Srednicki, Olive, Silk (1987), Bergstrom, Edsjo, Gondolo (1998),.., Blennow, Edsjo, Ohllson (2008),.., Siverston, Edsjo (2012) Milky Way Silk, Srednicki (1984), Ellis et al (1988), Turner, Wilczek (1990), Kamionkowski, Turner (1991), Bergstrom, Ullio, Buckley (1998),.. Erkoca, Reno, Sarcevic (2010) Dwarfs Evans, Ferrer, Sarkar (2003), Bergstrom, Hooper (2005),.. Sandick, Spolyar, Buckley, Freese, Hooper (2010) Clusters Yuan et al. (2010) Basudeb Dasgupta, IDM Chicago, 23 July

4 Where should we look for Dark Matter Annihilation? Basudeb Dasgupta, IDM Chicago, 23 July

5 Optimal Gamma Ray Sources Relative merits of DM sources for gamma ray detectors Basudeb Dasgupta, IDM Chicago, 23 July

6 Dwarf vs. Galaxy vs. Cluster Coma Galaxy cluster M31 Galaxy Angular Resolution of Fermi-LAT Angular Resolution of Fermi-LAT U. Ma. II Dwarf Gao, Frenk, Jenkins, Springel, White (2011) Basudeb Dasgupta, IDM Chicago, 23 July

7 Dwarfs vs. Clusters Clusters Dwarfs Sanchez-Conde, Cannoni, Zandanel, Gomez, Prada (2011) Basudeb Dasgupta, IDM Chicago, 23 July

8 Optimal DM Neutrinos Sources 1. Atmospheric neutrinos are the main background 2. Background neutrinos from Cosmic Ray sources 3. Typical Angular Resolution 1 4. Maximize DM/size and size > 1 Dwarfs have excess background from atm. nus Galactic Center is promising Galaxy Clusters are also promising We will discuss Galaxy Clusters Basudeb Dasgupta, IDM Chicago, 23 July

9 What is the expected signal? Test-Case: Virgo Cluster Basudeb Dasgupta, IDM Chicago, 23 July

10 Line of Sight Flux d = de Z 1 dn d h vi 2 8 m de Z Particle Physics Mass Cross Section Annihilation Channels and Spectra Basudeb Dasgupta, IDM Chicago, 23 July 2012 dl 2 [r(l), ] Astrophysics DM Profile 10

11 Particle Physics Inputs DM Mass and Cross Section are free parameters Neutrino Spectrum is model-dependent i) Annihilation to neutrino-pairs gives delta function energy spectra. Ideal case. ii) iii) Annihilation to muon-pairs gives boosted muon decay, i.e., hard spectrum. Annihilation to hadronically decaying particles gives typically soft spectrum. Basudeb Dasgupta, IDM Chicago, 23 July

12 Mass Distribution in Clusters CLASH project, arxiv: Basudeb Dasgupta, IDM Chicago, 23 July

13 Substructure Models Han et al. (based on Springel et al. 2011, i.e. Aquarius Project) Power-law extrapolation of halo mass function below resolution threshold for galaxy cluster simulations Boost about 1000 Agrees with Pinzke et al. (2011) Sanchez-Conde et al. (based on Kamionkowski, Kuhlen, Koushiappas 2010 based on Madau et al., Via Lactea) Uses 3K10 semi-analytical model of substructure in galaxies + rescaling of parameters to galaxy clusters Boost about 50 Basudeb Dasgupta, IDM Chicago, 23 July

14 Substructure Models NFW+sub (H) NFW+sub (SC) j( ) [radians] Basudeb Dasgupta, IDM Chicago, 23 July

15 Backgrounds Atmospheric neutrino flux very well measured. We used the parametrization by Erkoca, Reno, Sarcevic (2010) Cosmic rays from the Galaxy Cluster amount to < 1 neutrino per sq. deg. per year above 1 TeV Murase, Inoue, Nagataki (2008) Basudeb Dasgupta, IDM Chicago, 23 July

16 Track Signals dnµ deµ tracks NA T Adet = ( + Eµ ) Z 1 Eµ d de de CC (E )e L Pros: Enhanced Range Cons: higher backgrounds, and modest E resolution Basudeb Dasgupta, IDM Chicago, 23 July

17 Cascade Signals dn de = NA T Vcasc casc d e, + CC (E ) de NC (E ) d e,µ, de Pros: Low Bkg, Calorimetric Cons: lowered detection volume, poor directionality Basudeb Dasgupta, IDM Chicago, 23 July

18 KM3NeT-Core? IceCube has only degrees angular resolution on cascades. KM3NeT could improve that to 5-10 degrees Auer (2009) If KM3NeT also makes an inner detector, a la DeepCore, it could veto downgoing muons Could drastically improve low-energy sensitivity by looking at cascades Basudeb Dasgupta, IDM Chicago, 23 July

19 Results Basudeb Dasgupta, IDM Chicago, 23 July

20 Spatial Extent of the Signal Extended Signal Dasgupta and Laha (2012) Basudeb Dasgupta, IDM Chicago, 23 July

21 Ideal Sensitivity Can probe above to cm 3 s -1 Dasgupta and Laha (2012) Basudeb Dasgupta, IDM Chicago, 23 July

22 Hard Spectrum Dasgupta and Laha (2012) Can probe above to cm 3 s -1 Basudeb Dasgupta, IDM Chicago, 23 July

23 Relic Cross Section σv [10-26 cm 3 s -1 ] Canonical 3 2 This result 1 µ + µ - : WMAP+ACT u u: Fermi m [GeV] b b: Fermi Basudeb Dasgupta, IDM Chicago, 23 July τ + τ - : Fermi Steigman, Dasgupta and Beacom (2012)

24 Competitiveness Dasgupta and Laha (2012) Basudeb Dasgupta, IDM Chicago, 23 July

25 Low Energy Extension Basudeb Dasgupta, IDM Chicago, 23 July

26 Exotica Basudeb Dasgupta, IDM Chicago, 23 July

27 Neutrinophilic Dark Matter Sommerfeld-enhanced annihilation into neutrinos explains CDM problems at small-scales V only couples (decays) to neutrinos van den Arssen, Bringmann, Pfrommer, 2012 Basudeb Dasgupta, IDM Chicago, 23 July

28 Constraints on xx -> VV -> 4ν 20 yrs at KM3Net-Core Dasgupta and Laha (2010) Basudeb Dasgupta, IDM Chicago, 23 July

29 Summary Must detect DM in several channels and targets Tracks and Cascades Clusters are a good target IceCube/KM3NeT Can probe > ( ) x Relic Cross Section level Can be useful for some hard-to-kill models Basudeb Dasgupta, IDM Chicago, 23 July