Novel Searches for Dark Matter with Neutrino Telescopes
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Transcript of Novel Searches for Dark Matter with Neutrino Telescopes
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 1
Novel Searches for Dark Matter with Neutrino Telescopes Center for Cosmology and Astroparticle Physics Nov 17-18th,
2008
Prospects for the Search for Dark Matter with Fermi Brian L. WinerThe Ohio State UniversityFermi LAT Dark Matter and New Physics Working Group
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 2
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 3
WIMP annihilation: gamma-ray yield
200GeV mass WIMP
WIMP pair annihilation gamma spectrum
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 4
Dark Matter in the gamma ray skyMilky Way Halo simulated by Taylor & Babul (2005)
All-sky map of DM gamma ray emission (Baltz 2006)
Only dm annihilation radiation shown….
Galactic center
Milky Way halo
Milky Way satellites
Extragalactic sub haloes/clumps
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 5
Several Different Search Modes
Search Technique advantages challenges
Galactic center
Good Statistics
Source confusion/Diffuse background
Satellites, subhalosPoint 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
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 6
Total GCR protons GCR He GCR electrons albedo protons,pbar albedo positrons albedo electrons albedo gammas.
Background to all photons: Charged Particles
-Rejection power:
~105-6
-γ efficiency:
~0.8
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 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 > 1 GeV Truncated NFW Profile. Simulate Particle-yield (DarkSUSY) Background:
Astrophysical Sources Subtracted
GALPROP Represents Diffuse Background Simulate Detector Response.
Consider Annihilations: (Done Individually)
bb tt W W
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 8
Dark Matter From the Galactic Center
Simple for Test Statistic. (More sophisticated TS under study)
2- similar - WW less sensitivity- more sensitive.
tt
Current Efforts: Optimize ROI (Plot) Understand Source Removal
Need data. Optimize TS.
5 Years of Sky-Survey 5 Years of Sky-Survey
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 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 = R>10o or |b|>10o
NFW Profile. Diffuse Background:
GALPROP (Conv., Opt.) Simultaneous Fit to both
spatial and energydistributions
Mass vs < v> 1 year of running
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 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:
Strong, Moskalenko, Reimer, ApJ 537, 736, 2000
Strong, Moskalenko, Reimer, ApJ 613, 962-976, 2004
Conventional Optimized
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 11
Galactic Diffuse Background: Brem
l
b
E 100 MeV
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 12
Galactic Diffuse Background: Neutral Pion Decay
l
b
E 100 MeV
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 13
Galactic Diffuse Background: Inverse Compton
l
b
E 100 MeV
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 14
Galactic Diffuse Background: Total
l
b
E 100 MeV
b 10o
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 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 = R>10o or |b|>10o
NFW Profile. Diffuse Background:
GALPROP (Conv., Opt.) Simultaneous Fit to both
spatial and energydistributions
Mass vs < v> 1 year of running
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 16
Sensitivity for Galactic Halo Analysis
Conventional Diffuse Optimized Diffuse
Typical DM Photon Yields (1 year) : 1.5 x 104 (100 GeV/c2) 3 x 103 (250 GeV/c2)
50 50250 250
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 17
Halo Analysis: Mass Resolution
Warning: Statistical Uncertainty ONLY…think of this as a “best case/Lower Limit”
2501000
100
Current Efforts: Work on understanding
Diffuse Background. Optimize ROI Understand Source Removal Optimize Fitting. SYSTEMATICS! SYSTEMATICS!
For cases where we observer a signal at 5, we can determine our mass resolution.
Error bars represent the 68% CI
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 18
Search for Sub-halos
In CDM Paradigm, expect MW to contain potentially large number of sub-halos.
Sensitivity: Assumes Taylor&Babul (05) Distribution Sub-halo with Truncated NFW Profile MWIMP=100 GeV
Annihilation Background: Extragalactic,
Galactic Diffuse (GALPROP) Search for Msub>106 MO
Test Statistic:
v 2.310 26 cm3s 1
bb
lnL s b lnL(b)
.
8.9 kpc 2.7 107 Mo b = 39
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 19
Significance [ σ]
No
. o
f sa
tell
ites
Sub-halos
Fermi 1-yr
Fermi 5-yrs
WIMP mass [GeV]<σ
an
nihv >
* A
str
op
hy U
nc.
Green: GALPOP optimized
Red: GALPROP conventional
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.
99% CL
90% CL
68% CL
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 20
Dwarf Spheroidal Galaxies
Sagittarius DwarfAssumes 5 years of observations.
Likelihood TS: Sensitivity Improves by2-4x
Advantage: Could be DM Dominated
Disadvantage: DM Profile?
Initial Sensitivity GALPROP used for
Diffuse Test Statistic:
Simple: Recent: Likelihood
If NFW Profile, sens afactor of 10 less.
Other dSph (e.g. Draco)will also be studied.
2
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 21
Line Search Simulated detector response to δ function in energy
)()( 2min
2min
2 bbs
Advantage: ”Smoking Gun” Backgrounds from data
Challenges: Small BR <10-3
Energy Resolution. Initial Sensitivity Estimation
ROI = Broken Annulus 20o < R < 35o ; |b|>15o DM Den High but reduced
background Scan through energy range Fit Background to exponential Signal Fit Double Gaussian Test Statistic:
Example MC Sim.
Proposed by Stoehr, et al
Some recent models predict enhancements.
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 22
Line 5σ sensitivity
5 Years of Fermi Data
Current Efforts: Improved event selection and
energy reconstruction. Optimized ROI
Need data Measure Diffuse Bkg. Optimize TS.
Trials factor included for unknown source.
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 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!
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 24
WIMP annihilation: gamma-ray fluxWIMP annihilation: gamma-ray flux
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 25
Acknowledgements
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)
Pre-launch Estimates for GLAST Sensitivity to Dark Matter Annihilation SignalsE. A. Baltz, et al JCAP, 07 (2008) 013, arXiv: 0806.2911v2
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 26
Parameter Space
Brian L. Winer, Ohio State University Fermi Gamma-Ray Space Telescope CCAPP DM Workshop Page 27
Cosmological WIMPS