1. Search for Dark Matter
physics 805
fall 2008

2. WIMP search strategies
Direct detection
Indirect detection: – neutrinos from the Earth/Sun – antiprotons from the galactic halo – positrons from the galactic halo – gamma rays from the galactic halo – gamma rays from external galaxies/halos – synchrotron radiation from the galactic center / galaxy clusters – ...

3. direct detection - general principles
WIMP + nucleus  WIMP + nucleus
Measure the nuclear recoil energy
Suppress backgrounds c c c
Search for an annual modulation due to the Earth’s motion around the Sun
December
June

7. present limits

8. DAMA result (> 8 sigma)

9. WIMP Capture and Annihilationnm
DETECTOR
c + c  W + W  n + n

10. 7 IceCube + 18 AMANDA strings
Inner Core Detector
Inner Core
(same region
as AMANDA)
7 IceCube + 18 AMANDA strings
225 DOMs OMs

11. neutralino capture and annihilationrc
velocity
distribution
sscatt
Gcapture
Gannihilation
n interactions
n int.
m int. c
sun nm m
Freese, ’86; Krauss, Srednicki & Wilczek, ’86 Gaisser, Steigman & Tilav, ’86
Silk, Olive and Srednicki, ’85 Gaisser, Steigman & Tilav, ’86

12. indirect detection for cyclists
e.g. 104 m2 n-telescope searches for 500 GeV WIMP
300 km/s
> LHC limit
1.  - flux
2. solar cross section

13. Nsun = capture rate = annihilation rate_
c c WW
250 GeV
500 GeV
mnm
3. Capture rate by the sun
4. Number of muon-neutrinos
0.1 is the leptonic branching ratio

14. 5.5 x 1023 cm-3
104 m2 _ ~
# events = 10 per year

15. WIMP search Limits on muon flux from Earth
PRELIMINARY
Limits on muon flux from Earth
Limits on muon flux from Sun
AMANDA 180d
Antares 3 years
1km3 (IceCube) SK
New solar system WIMP diffusion model -> more realistic neutralino velocity distribution (Lundberg&Edsjoe)
Detection threshold (mu): ~50GeV (extrapolate to get limits for E>1 GeV)
Cuts optimized for each mass independently
Disfavored by direct search (CDMS II)

16. IceCube 22 strings

17. Status indirect search

18. IceCube Direct Detection vs Black: out Green: yes Blue: no
(Zeppelin4/Genius)
Black: out
Green: yes
Blue: no