Transcript Search for Dark Matter - IceCube Neutrino Observatory

Search for Dark Matter
physics 805
fall 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
– ...
direct detection - general
principles
c
c
• WIMP + nucleus 
WIMP + nucleus
• Measure the nuclear recoil
energy
• Suppress backgrounds
c
December
c
c
June
• Search for an annual
modulation due to the
Earth’s motion around
the Sun
present limits
DAMA result (> 8 sigma)
WIMP Capture and Annihilation
c
nm
n
DETECT
c+cW+Wn+n
Inner Core Detector
Inner Core
(same region
as AMANDA)
7 IceCube + 18 AMANDA strings
225 DOMs + 540 OMs
neutralino capture and annihilation
rc c
sun
velocity
distribution
n interactions
sscatt
nm
n int.
m int.
Gcapture
m
Gannihilation
cc 
qq
ll
 nm


W , Z,H
Silk, Olive and Srednicki, ’85
Gaisser, Steigman & Tilav, ’86




 cc ,bb ,tt ,   ,W , Z , H H
0
0
Freese, ’86; Krauss, Srednicki &
Wilczek, ’86 Gaisser, Steigman &
Tilav, ’86
indirect detection for cyclists
e.g. 104 m2 n-telescope searches for 500 GeV WIMP
300 km/s
1. c - flux
> LHC limit
500GeV
 c  r c v  2.4 x 10 [
] cm 2 s 1
mZ
4
0.4 GeVcm
3
500GeV
 8 x 10 [
] cm 3
mZ
4
2. solar cross section
 sun  ns cp
( GF m )
2
p
Msun

s cp
mp
 [ 1.2 x 10
57
][ 10
41
cm ]
2
G
~
M
2
F
2
Z
2
2 MZ
mH4
Nsun = capture rate = annihilation rate
_
cc
500 GeV
WW
250 GeV
mnm
3. Capture rate by the sun
Nsun  c sun  3 x 10 s
20
4. Number of muon-neutrinos
Nn  2 x 0.1 Nsun
1
Nn
8
2 1
n 
 2 x 10 cm s
2
4 d
5.5 x 1023 cm-3
events  area time n rice sn Rm
104 m2
sn  10 38 cm2 En ( GeV )  2.5 x 10 36 cm2
~
_ 1
Rm  5 m E m ( GeV )  625 m ( E m  En )
2
# events = 10 per year
WIMP search
Limits on muon flux from Earth
Limits on muon flux from Sun
AMANDA 180d
SK
Disfavored by
direct search
(CDMS II)
Antares 3 years
1km3 (IceCube)
IceCube 22 strings
Status indirect search
IceCube
vs
Direct
Detection
(Zeppelin4/Genius)
Black: out
Green: yes
Blue: no