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Novel Searches for Dark Matter with Neutrino Telescopes

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Title: Slide 1 Author: Brian Winer Last modified by: mcgarry Created Date: 11/17/2008 2:31:48 AM Document presentation format: Custom Company: The Ohio State University – PowerPoint PPT presentation

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Title: Novel Searches for Dark Matter with Neutrino Telescopes


1

Prospects for the Search for Dark Matter with
Fermi Brian L. Winer The Ohio State
University Fermi LAT Dark Matter and New Physics
Working Group
Novel Searches for Dark Matter with Neutrino
Telescopes Center for Cosmology and
Astroparticle Physics Nov 17-18th, 2008
2
(No Transcript)
3
WIMP annihilation gamma-ray yield
200GeV mass WIMP
WIMP pair annihilation gamma spectrum
4
Dark Matter in the gamma ray sky
Milky Way Halo simulated by Taylor Babul
(2005) All-sky map of DM gamma ray emission
(Baltz 2006)
Galactic center
Milky Way satellites
Milky Way halo
Extragalactic
sub haloes/clumps
Only dm annihilation radiation shown.
5
Several Different Search Modes
Search Technique advantages challenges
Galactic center Good Statistics Source confusion/Diffuse background
Satellites, subhalos Point sources Low background, Good source id Low statistics
Milky Way halo Large statistics Galactic diffuse background
Extra- galactic Large Statistics Astrophysics, galactic diffuse background
Spectral lines No astrophysical uncertainties, good source id Low statistics
6
Background to all photons Charged Particles
  • Rejection power
  • 105-6
  • ? efficiency
  • 0.8

Total GCR protons GCR He GCR electrons
albedo protons,pbar albedo positrons
albedo electrons albedo gammas.
7
Galactic Center
  • Advantage Largest Source of
    DM Photons
  • Problems
  • Astrophysical Sources
  • CR Accelarators
  • High Energy Gamma Sources
  • Behavior at Fermi Energies??
  • Initial Sensitivity Estimation
  • ROI 0.5 deg of GC, E gt 1 GeV
  • Truncated NFW Profile.
  • Simulate Particle-yield (DarkSUSY)
  • Background
  • Astrophysical Sources Subtracted
  • GALPROP Represents Diffuse Background
  • Simulate Detector Response.

Consider Annihilations (Done Individually)
8
Dark Matter From the Galactic Center
Simple for Test Statistic. (More
sophisticated TS under study)
  • similar
  • WW less sensitivity
  • more sensitive.

5 Years of Sky-Survey
5 Years of Sky-Survey
9
Galactic Halo Analysis
  • Advantage
  • Use the large statistics of the full sky.
  • Challenge
  • Critically Dependent on Diffuse Background
  • Measure the sensitivity to observing a signal.
  • ROI Rgt10o or bgt10o
  • NFW Profile.
  • Diffuse Background
  • GALPROP (Conv., Opt.)
  • Simultaneous Fit to bothspatial and
    energydistributions
  • Mass vs lts vgt
  • 1 year of running

10
Galactic diffuse conventional and optimized
GALPROP model
  • conventional GALPROP
  • calibrated with locally measured electron and
    proton,helium spectra, as well as synchrotron
    emission
  • Optimized GALPROP

Conventional
Optimized
Strong, Moskalenko, Reimer, ApJ 537, 736, 2000
Strong, Moskalenko, Reimer, ApJ 613, 962-976,
2004
11
Galactic Diffuse Background Brem
b
l
12
Galactic Diffuse Background Neutral Pion Decay
b
l
13
Galactic Diffuse Background Inverse Compton
b
l
14
Galactic Diffuse Background Total
b
l
15
Galactic Halo Analysis
  • Advantage
  • Use the large statistics of the full sky.
  • Challenge
  • Critically Dependent on Diffuse Background
  • Measure the sensitivity to observing a signal.
  • ROI Rgt10o or bgt10o
  • NFW Profile.
  • Diffuse Background
  • GALPROP (Conv., Opt.)
  • Simultaneous Fit to bothspatial and
    energydistributions
  • Mass vs lts vgt
  • 1 year of running

16
Sensitivity for Galactic Halo Analysis
Conventional Diffuse
Optimized Diffuse
50
250
50
250
Typical DM Photon Yields (1 year) 1.5 x 104
(100 GeV/c2) 3 x 103 (250 GeV/c2)
17
Halo Analysis Mass Resolution
Warning Statistical Uncertainty ONLYthink of
this as a best case/Lower Limit
100
For cases where we observer a signal at 5s, we
can determine our mass resolution.
Error bars represent the 68 CI
  • Current Efforts
  • Work on understanding Diffuse Background.
  • Optimize ROI
  • Understand Source Removal
  • Optimize Fitting.
  • SYSTEMATICS! SYSTEMATICS!

0
250
100
18
Search for Sub-halos
  • In CDM Paradigm, expect MW to contain potentially
    large number of sub-halos.
  • Sensitivity
  • Assumes TaylorBabul (05) Distribution
  • Sub-halo with Truncated NFW Profile
  • MWIMP100 GeV
  • Annihilation
  • Background Extragalactic,Galactic Diffuse
    (GALPROP)
  • Search for Msubgt106 MO
  • Test Statistic

.
19
Sub-halos
Most Sub-Halos are found a high (b) galactic
latitude. Once found an attempt can be made to
extract the DM parameters. Below are the error
ellipses for the case on the previous page.
Green GALPOP optimized Red GALPROP conventional
No. of satellites
Fermi 5-yrs
99 CL
90 CL
Fermi 1-yr
68 CL
ltsannihv gt Astrophy Unc.
Significance s
WIMP mass GeV
20
Dwarf Spheroidal Galaxies
  • Advantage
  • Could be DM Dominated
  • Disadvantage
  • DM Profile?
  • Initial Sensitivity
  • GALPROP used forDiffuse
  • Test Statistic
  • Simple
  • Recent Likelihood
  • If NFW Profile, sens afactor of 10 less.
  • Other dSph (e.g. Draco)will also be studied.

Sagittarius Dwarf Assumes 5 years of observations.
Likelihood TS Sensitivity Improves by2-4x
21
Line Search
Simulated detector response to d function in
energy
  • Advantage Smoking Gun
  • Backgrounds from data
  • Challenges
  • Small BR lt10-3
  • Energy Resolution.
  • Initial Sensitivity Estimation
  • ROI Broken Annulus
  • 20o lt R lt 35o bgt15o
  • DM Den High but reduced background
  • Scan through energy range
  • Fit Background to exponential
  • Signal Fit Double Gaussian
  • Test Statistic

Some recent models predict enhancements.
Proposed by Stoehr, et al
Example MC Sim.
22
Line 5s sensitivity
Trials factor included for unknown source.
5 Years of Fermi Data
  • Current Efforts
  • Improved event selection and energy
    reconstruction.
  • Optimized ROI
  • Need data ? Measure Diffuse Bkg.
  • Optimize TS.

23
Summary
  • Fermi has many targets for the indirect DM
    search.
  • Some are statistics limited.
  • Some are sys. limited
  • Other Modes
  • Cosmological WIMPS
  • Extra Dim KK ? HE Electrons
  • Efforts are on-going to optimize these searches.
  • Real Data Helps!
  • The DM Working Group plans an intense effort in
    the first year of operation.
  • We are happy finally to be in orbit!

24
WIMP annihilation gamma-ray flux
25
Acknowledgements
Pre-launch Estimates for GLAST Sensitivity to
Dark Matter Annihilation SignalsE. A. Baltz, et
al JCAP, 07 (2008) 013, arXiv 0806.2911v2
  • E Baltz, B. Berenji, E. Bloom, J. Chiang, Y.
    Edmonds, G. Godfrey, P. Wang, L. Wai, J.
    Cohen-Tanugi(SLAC/KIPAC)
  • I. Moskalenko (Stanford)
  • A. Morselli, A. Lionetto (INFN Roma/Tor Vergata)
  • E. Nuss (Montpellier)
  • R. Hughes, A. Sander, P. Smith, B. Winer (Ohio
    State)
  • L. Bergström, T. Bringmann, J. Conrad, J. Edsjö,
    A. Sellerholm (Stockholm)
  • A. Moiseev (Goddard)
  • G. Bertone (Paris)
  • R. Johnson(Santa Cruz)
  • J. Ormes (Denver)
  • R. Rando (Padova)
  • A. Strong (Max-Planck)

26
Parameter Space
27
Cosmological WIMPS
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