Indirect Detection - Parallel Session I IDM 2012, Chicago Probing Dark Matter in Galaxy Clusters using Neutrinos In Collaboration with Ranjan Laha, arxiv/1206.1322 + PRD Basudeb Dasgupta CCAPP, Ohio State University
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 2012 2
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 2012 3
Where should we look for Dark Matter Annihilation? Basudeb Dasgupta, IDM Chicago, 23 July 2012 4
Optimal Gamma Ray Sources Relative merits of DM sources for gamma ray detectors Basudeb Dasgupta, IDM Chicago, 23 July 2012 5
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 2012 6
Dwarfs vs. Clusters Clusters Dwarfs Sanchez-Conde, Cannoni, Zandanel, Gomez, Prada (2011) Basudeb Dasgupta, IDM Chicago, 23 July 2012 7
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 2012 8
What is the expected signal? Test-Case: Virgo Cluster Basudeb Dasgupta, IDM Chicago, 23 July 2012 9
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
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 2012 11
Mass Distribution in Clusters CLASH project, arxiv:1107.2649 Basudeb Dasgupta, IDM Chicago, 23 July 2012 12
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 2012 13
Substructure Models 10 3 10 2 NFW+sub (H) NFW+sub (SC) j( ) 10 1 10 0 10-1 10-5 10-4 10-3 10-2 10-1 [radians] Basudeb Dasgupta, IDM Chicago, 23 July 2012 14
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 2012 15
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 2012 16
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 2012 17
KM3NeT-Core? IceCube has only 30-50 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 2012 18
Results Basudeb Dasgupta, IDM Chicago, 23 July 2012 19
Spatial Extent of the Signal Extended Signal Dasgupta and Laha (2012) Basudeb Dasgupta, IDM Chicago, 23 July 2012 20
Ideal Sensitivity Can probe above 10-23 to 10-24 cm 3 s -1 Dasgupta and Laha (2012) Basudeb Dasgupta, IDM Chicago, 23 July 2012 21
Hard Spectrum Dasgupta and Laha (2012) Can probe above 10-23 to 10-24 cm 3 s -1 Basudeb Dasgupta, IDM Chicago, 23 July 2012 22
Relic Cross Section σv [10-26 cm 3 s -1 ] 10 9 8 7 6 5 4 Canonical 3 2 This result 1 µ + µ - : WMAP+ACT 0 1 2 5 10 20 50 100 u u: Fermi m [GeV] b b: Fermi Basudeb Dasgupta, IDM Chicago, 23 July 2012 23 τ + τ - : Fermi Steigman, Dasgupta and Beacom (2012)
Competitiveness Dasgupta and Laha (2012) Basudeb Dasgupta, IDM Chicago, 23 July 2012 24
Low Energy Extension Basudeb Dasgupta, IDM Chicago, 23 July 2012 25
Exotica Basudeb Dasgupta, IDM Chicago, 23 July 2012 26
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 2012 27
Constraints on xx -> VV -> 4ν 20 yrs at KM3Net-Core Dasgupta and Laha (2010) Basudeb Dasgupta, IDM Chicago, 23 July 2012 28
Summary Must detect DM in several channels and targets Tracks and Cascades Clusters are a good target IceCube/KM3NeT Can probe > (100-1000) x Relic Cross Section level Can be useful for some hard-to-kill models Basudeb Dasgupta, IDM Chicago, 23 July 2012 29