Search for Dark Matter

physics 805fall 2008

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– ...

• Search for an annual modulation due to the Earth’s motion around the Sun

direct detection - general principles

• WIMP + nucleus WIMP + nucleus

• Measure the nuclear recoil energy

• Suppress backgrounds

December June

present limits

DAMA result (> 8 sigma)

WIMP Capture and Annihilation

DETECTOR

n

+ W + W +

Inner Core Detector

Inner Core(same regionas AMANDA)

7 IceCube + 18 AMANDA strings

225 DOMs + 540 OMs

neutralino capture and annihilation

sun

Freese, ’86; Krauss, Srednicki &Wilczek, ’86 Gaisser, Steigman & Tilav, ’86

velocitydistribution

scatt

capture

annihilation

interactions

int. int.

cc ,bb , tt , ,W, Z 0, HH 0

qq ll

W, Z,HSilk, Olive and Srednicki, ’85Gaisser, Steigman & Tilav, ’86

indirect detection for cyclists

e.g. 101044 m m22 -telescope searches for 500 GeV WIMP

> LHC limit1. - flux 300 km/s

2. solar cross section

12

Z

4 scm]mGeV500[10x4.2v

3

Z

43 cm]mGeV500[10x8GeVcm4.0

]cm10][10x2.1[

mMn

24157

pp

sunpsun

2Z

2F

mM22

pF

MG~

)mG( 4H

2Z

Nsun = capture rate = annihilation rate

_ WW

250 GeV250 GeV500 GeV

3. Capture rate by the sun

4. Number of muon-neutrinos

120sunsun s10x3N

sunN1.0x2N

is the leptonic branching ratio

5.5 x 1023 cm-3

104 m2

~~__

# events = 10 per year

1282 scm10x2

d4N

Rtimeareaevents ice

)E21E(m625)GeV(Em5R

cm10x5.2)GeV(Ecm10 236238

Disfavored by direct search (CDMS II)

Limits on muon flux from Earth Limits on muon flux from Sun

WIMP search

PRELIMINARY

1km3 (IceCube)

AMANDA 180d

Antares 3 yearsSK

IceCube 22 strings

Status indirect search

DirectDetection

(Zeppelin4/Genius)

Black: outGreen: yes

Blue: no

IceCubevs