• we built a km3 neutrino detector 3 challenges: • drilling • optics of ice • atmospheric muons • atmospheric neutrino spectrum • atmospheric.
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Transcript • we built a km3 neutrino detector 3 challenges: • drilling • optics of ice • atmospheric muons • atmospheric neutrino spectrum • atmospheric.
• we built a km3 neutrino detector 3 challenges:
• drilling
• optics of ice
• atmospheric muons
• atmospheric neutrino spectrum
• atmospheric muon spectrum: first surprise
• search for the sources of the Galactic cosmic rays
• search for the extragalactic cosmic rays
• gamma ray bursts
• GZK neutrinos
• a multi-wavelength story
• search for dark matter
IceCube.wisc.edu
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)
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
supersymmetry on
the back of an
envelope
arXiv 9404252
WIMP Capture and Annihilation
c
nm
n
DETECT
c+cW+Wn+n
indirect detection for cyclists
e.g. n-telescope searches for 500 GeV WIMP
1. c - flux
300 km/s
> LHC limit
500GeV
c r c v 2.4 10 [
] cm2 s 1
mc
500GeV
0.4 GeV cm3 8 104 [
] cm3
mc
4
2. solar cross section
sun n s c p
M sun
sc p
mp
[1.2 1057 ][10 41 cm2 ]
( GF m )
2
p
G
~
M
2
F
2
Z
2
2 MZ
mH4
Nsun = capture rate = annihilation rate
c c W W
mnm
500 GeV
250 GeV
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
# events A E 250GeV n runningtime
10 cm
2
2
# events = 60 per year
update: focus region
neutrino rate versus WIMP mass
white line: 100 events km-2 yr-1
IC22
solar neutrino rate
vs wimp mass
0—1 TeV
100 events km-2 yr-1
• capture
• equilibrium
dN
2
Ccap Cann N
dt
1
1
2
Gann Cann N Ccap
2
2
neutrino flux
indirect detection
of
dark matter wimp-nucleon cross
section
the sun
atmospheric neutrino events
sensitivity to wimps with
spin-independent interactions
<103 SI limit
>103 SI limit
arXiv:0906.1615
arXiv:0906.1615
neutrinos from the
center of the
Galaxy
conclusions
• supersymmetry comes in 2 flavors:
spin-independent ( favors direct detection
because of A2 ) and spin-dependent
• IceCube is competitive for spin-dependent
• can probe most of the interesting parameter
space of the MSSM
• [astrophysics is known ( no toothfairies )]
IceCube: multiwavelength analysis
•
•
•
•
•
IceCube
supernova explosions (millisecond alert)
a story from AMANDA days
TeV gamma ray observations
GRB
IceCube takes data continuously
and records and archives them
supernova burst: light fromn e
PMT noise low (280 Hz)
detect correlated rate increase
on top of PMT noise when
supernova neutrinos pass
through the detector
p ne
Kitaura, Janka, Hillebrandt (Astron. Astrophys. 450 (2006) 345)
Garching
first 20 msec
e p n n e
Simulation Data
deleptonization
Luminosities
starting points of neutrino showers
• equivalent detection volume
of a 2.5 megaton SuperK-style
detector
• 1 million events from 10 kpc
• time of neutronization to a few
milliseconds
106 eventswith1.7m sec sampling
start : 3m sat 95% CL
signal depends on
• properties of the supernova collapse
• unknown neutrino physics
Kamioka II
1987A
Participation in SNEWS
…several hours advanced notice to astronomers …
Super-K
SNO
coincidence
server @ BNL
alert
LVD
AMANDA
(IceCube)
IceCube will follow this year
http://snews.bnl.gov astro-ph/0406214