Transcript Direct Dark Matter Searches

Searches for Dark
Matter
A. Bashir, U. Cotti, C. de Leon, A. Raya, V.
Villanueva and L. Villaseñor
IFM-UMSNH
XI Workshop on Particles & Fields DPyCSMF
Tuxtla Gutierrez, Chiapas
1
Outline
 Evidences
for Dark Matter
 DM Candidates
 Direct & indirect detection
 Running & future experiments
 Conclusion
2
A Mexican
group submitted
a proposal to
study DM in an
underground lab
to Conacyt in
2007
R&D
money will
possibly be
granted in
2008
3
Evidence for Dark Matter
Fritz Zwicky
(1933) measured
the
velocities of the
individual
galaxies. He
concluded that
“dark” matter is
required to hold
the cluster
Coma cluster, 350 M ly
4
Evidence for Dark Matter

Flat Rotation curves
of Galaxies. V. Rubin
and W.K. Ford (1970)
•
“What you see is not what you get.”
vc ~ r 1/2
Alternative Explanations
 Local
density :
0.3

Modified Newtonian Dynamics
(Moglim 1983)

Modified Gravity such as Scalar tensor
vector gravity theory (Moffat 2006)
5
Measured
over and
over
Each plot
contains
50-100
galaxies
according to
luminosity
M. Persic et al. 1996
6
BB Nucleogenesis: Determines the present baryon mass
density to only ~ 4% of critical density
Widths of curves
indicate 95% CL
for the abundance
predictions
Measurements are
shown as boxes.
Non baryon dark mass
is required!
D. Tytler, J. M. O’Meara, N.
Suzuki, and D. Lubin, astroph/0001318
7
Evidence for Dark Matter
Bullet Cluster
(Clowe et al., 2006)
two colliding
Clusters of
Galaxies at a
distance of about
3.4 billion light
years
White – Visible
Red – X Rays
Blue - Grav. Lensing
evidence against
Modified Newtonian
Dynamics (MOND)
NASA RELEASE 06-297: "These observations provide the strongest evidence yet
8
that most of the matter in the universe is dark"
White – Visible
Blue - Grav. Lensing
Red – X Rays
White – Visible
Red – X Rays
Blue - Grav. Lensing
Evidence for Dark Matter
Lambda-Cold Dark Matter (concordance) model explains cosmic microwave
background observations (WMAP), as well as large scale structure observations (Sloan
Digital Sky Survey) and supernovae Ia data of the accelerating expansion of the
universe.
The Composition of the Universe
13
ΛCDM MODEL
(Spergel et al. 2006)
14
Particle Candidate for Cold
Dark Matter: WIMP
Weakly Interacting Massive Particle





Stable, TeV scale, electrically neutral, only
weakly interacting
No such candidate in the Standard Model
Good candidate: neutralino, Lightest
Supersymmetric Particle (LSP) in SUSY with m
~ 10 GeV to 10 TeV
Linear combination of the zino, the photino and
the neutral higgsinos
May be produced at the LHC
Particle Candidate for Dark
Matter

But there are many other possibilities (technibaryons, gravitino, axino, invisible axion,
WIMPZILLAS( Godzilla-sized version of WIMPS,
ruled out by Auger data), etc)
WIMP Dark Matter
Comoving number density

Increasing
<Av>


Nequillibrium
X=m/Temperature (time )
E.W. Kolb and M.S. Turner, The Early Universe

Produced in early
Universe
They are in thermally
equilibrium at high
temperature
Decouple when
expansion rate ~
interaction rate
Density left-over from
annihilation depends
on cross section

CDMS-II, ZEPLIN
Edelweiss,
DAMA, GENIUS,
etc



f
Direct Detection
of halo
particles in
terrestrial
detectors
f
WIMP DETECTION
Scattering
19
(direct) Detection method

Since they are neutral and stable, what we
can expect is only a collision with ordinary
matter.
Dark Matter
particles

Energy deposit
Electron recoil does not give enough
energy but nuclear recoil gives ~100keV if
mDM~O(100GeV).
WIMP DETECTION

f

f
Indirect Detection
 SuperK, AMANDA,
ICECUBE, GLAST
Annihilation
•Search for neutrinos, gamma rays, radio waves, antiprotons, positrons in earth- or
space-based experiments
Direct and indirect

_
p

e+


methods are
complementary
techniques along
with a possible
discovery at the
LHC
21
WIMP signatures (Direct Det)

Nuclear recoils
(produce similar recoils with sigma 1020
higher, 108-9 background reduction needed
 Neutrons

Recoil spectrum shape
 Exponential
(as most bkg)
 Shape for backgrounds : electron/nuclear recoils




Absence of multiple scattering (against neutron)
Uniform rate throughout volume (against surface
radioactivity)
Directionality of nuclear recoils
Annual rate modulation
22
WIMP signatures (Direct Det)
23
Current direct detection
experiments
Discriminati
on
Name
CUORICINO
Location
Gran Sasso
Technique
Heat
Material
41 kg TeO2
Status
running
GENIUS-TF
Gran Sasso
Ionization
10 to 40 kg Ge in N2
running ???
HDMS
Gran Sasso
Ionization
0.2 kg Ge diodes
stopped
IGEX
Canfranc
Ionization
2 kg Ge Diodes
stopped
DAMA
Gran Sasso
Light
100 kg NaI
stopped
LIBRA
Gran Sasso
Light
250 kg NaI
running
NaIAD
Boulby mine
Light
46 kg NaI
stopped
ZEPLIN-I
Boulby mine
Light
4 kg Liquid Xe
stopped
XENON
Surface to
GS
Light+ Ionization
3 to 10 kg Liquid Xe
running
ZEPLIN II
Boulby mine
Light+ Ionization
6 kg Liquid Xe
running
CDMS-I
Stanford
Heat + Ionization
1 Kg Ge + 0.2 Kg Si
stopped
CDMS-II
Soudan mine
Heat + Ionization
2 to 7 kg Ge + 0.4 to 1.4
Kg Si
running
CRESST-I
Gran Sasso
Heat + Light
0.262 kg Al2O3
stopped
CRESST-II
Gran Sasso
Heat + Light
0.6 to 9.9 kg CaWO4
running
EDELWEISS-I
Modane
Heat + Ionization
1 kg Ge
stopped
EDELWEISSII
Modane
Heat + Ionization
10 to 30 kg Ge
In istallation
PICASSO
SNO
Bubble chamber
20 g Freon
24
running
B. Sadoulet
KEKTC6
25
90% C.L. exclusion limits on WIMPnucleon scattering cross-section (spinindependent)
CDMS (2006)
26
CDMS II
Spin
independent
90%
Exclusion
limits
split-SUSY
mSUGRA




Based in Gran Sasso lab
(3500 mwe)
100 kg of NaI(Tl)
Exposure : 107731 kg.d
Coincidence between 2 PMTs
Pulse shape rejection inefficient
at 2 keVee
NaI
NaI
NaI
NaI
PMT

PMT
NaI scintillation : DAMA
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NaI scintillation : DAMA


Used annual modulation
Claim annual modulation at
6.3σ over 7 annual cycles




Mχ ~ 52 GeV/c²
σn ~ 7.2 10-6 pb
Not compatible with other
experiments (CDMS, ZEPLIN,
EDELWEISS)
Future = LIBRA (250 kg of NaI)
DM density ~0.3GeV/cc
Single-hits events residual rates
100GeV WIMPs  1 WIMP / 7cm cubic, =105/cm2/sec
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CDMS II at Soudan
Log10(Muon Flux) (m-2s-1)
Depth of 2000 mwe reduces neutron background from
~1 / kg / day to ~1 / kg / year
Stanford Underground
Facility
500 Hz muons
in 4 m2 shield
Muon-veto paddles encasing outer
lead and polyethylene shielding
Dilution
Refrigerator
Electronics stem
from Icebox
1 per
minute
in 4 m2 shield
Icebox can take 7 towers
with 6 ZIP detectors each
Depth (mwe)
Cold stem to
Icebox
Experimental apparatus
Heat-ionization: CDMS-II
FET cards
SQUID cards




4x250g Ge +
2x100g Si
Net exposure: 19.4
kg.d
Detector = ZIP
(sensitive to athermal
phonon)
Active muon veto +
shielding (PE + Pb)
4K
0.6 K
0.06 K
0.02 K
ZIP 1 (Ge)
ZIP 2 (Ge)
ZIP 3 (Ge)
ZIP 4 (Si)
ZIP 5 (Ge)
ZIP 6 (Si)
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CDMS II Detector Deployment
•Identical Icebox as CDMS I, but fits seven towers.
• Each tower (T1-7) contains three Ge and three Si ZIP detectors
interlaced.
 Total
mass of Ge = 7 x 3 x 0.25 kg > 5 kg
 Total mass of Si = 7 x 3 x 0.10 kg > 2 kg
(Extra polyethylene shield in SUF icebox only
allows 3 towers to be run at SUF simultaneously.)
T3
T4
T1
T2
T7
T5
T6
Heat-ionization: CDMS-II

Rejection of background surface events with
timing cuts
33
• CDMS I (1995-1999)
Results
for scalar-interacting (~A2) WIMPs probed are best upper limits of any
experiment for the mass range 10 to 35 GeV.
CDMS data are incompatible with DAMA signal at high confidence.
Sensitivity limited by external neutron background from muons interacting in
surrounding rock.
• CDMS II (1999-2005)
Construction
underway at deep site: Soudan, Minnesota.
First tower of 6 detectors ready for Soudan - they exceed performance
expectations - “First Dark” January 2003.
Reduction of neutron background by factor of 2.3 due to installation of internal
moderator in agreement with Monte Carlo predictions.
More work required on surface-beta rejection/identification/subtraction in order
to fully utilize deep site?
Neutrinos
from the Earth
(& Sun – but
Sun more
difficult for
AMANDA 
IceCUBE)
Ice
Cube




•
•
•
AMANDA’s BIG BROTHER: 1 km3 of Ice
4200 PMTs on 70 Strings 1450-2450 m
~10 Angular Resolution to Mu Neutrinos
IceTop Air Shower Array to
Veto Downgoing Muons
Digitized/Time-Stamped at
Each PMT
Started Deploying 2005;
Construction Finished ~2011
Gamma-ray Large Area Space Telescope GLAST
Large Area Telescope (LAT)
GLAST will have a very broad science
menu that includes:
• Systems with supermassive black holes
(Active Galactic Nuclei)
• Gamma-ray bursts (GRBs)
• Pulsars
• Solar physics
• Origin of Cosmic Rays
• Probing the era of galaxy formation, opticalUV background light
• Solving the mystery of the high-energy
unidentified sources
• Discovery! Particle Dark Matter? Other
relics from the Big Bang? Extra dimensions?
Testing Lorentz invariance. New source
classes.
GLAST will search for WIMP
annihilation gamma rays from
galactic center, galactic halo,
galactic satellites and extragalactic
To be launched in late 2007, will survey the
gamma-ray sky in the energy range of 20MeV300 GeV.
Kathy Turner, 24May2006
37
Conclusion
• The existence of Nonbaryonic Dark Datter has
•
•
•
•
•
•
been definitely established
CDM is favoured
Supersymmetric particles (in particular,
neutralinos) are still among the best-motivated
candidates
New direct and indirect detection experiments
will reach deep into theory parameter space
The various indirect and direct detection
methods are complementary to each other and to
LHC
The hunt is going on – many new experiments
coming!
The dark matter problem may be near its
(s)solution…