KIT – University of the State of Baden-Württemberg and
National Large-scale Research Center of the Helmholtz Association
Klaus Eitel, Karlsruhe Institute of Technology, KCETA, IK
www.kit.edu
Dark Matter -- Astrophysical Evidences
and Terrestrial Searches
Institute for Nuclear Physics2 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Content of the lecture
review of astrophysical evidences for DM
cosmological LCDM concordance model
structure formation
DM in our neighbourhood
DM particle candidates: axions, neutralinos, ...
interaction models of DM with ordinary matter
indirect detection (cc annihilation) & production
direct detection strategies
methods of direct detection
general challenges
experiments for direct search (I)
experiments for direct search (II)
results – evidences?
direct indirect production
actual status (and outlook)
Lecture 1:
Lecture 2:
Lecture 3:
Lecture 4:
Institute for Nuclear Physics3
WIMP
Heat
Ionization
Light
Ge, CF3I, C4F10
liquid Xe/Ar
NaI, liqu.Xe
Ge, Si
CaWO4, BGO
Al2O3, LiF
…via elastic scattering off nuclei
1% energyfastestno surface effects
10% energy
100% energyslowestcryogenics
WIMP
Target
Edelweiss,
CDMS
CRESST-2
Zeplin-3 , LUX,
Xenon-10/100
DAMA, Libra, Zeplin-1,
XMASS, KIMS, ANAIS
CRESST-1
HDMS
CoGeNT
COUPP
Picasso
WArP, ArDM
direct DM search – detection schemes
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Institute for Nuclear Physics4 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
direct DM search with ultralow noise
ionization detectors – CoGeNT
Ge target
to investigate low mc
low threshold
small target mass
(475g)
(330 m.w.e., part of
Chicago’s Tunnel
And Reservoir Plan)JCAP09(2007)009
p-type point contact (PPC)
Germanium detector (HPGe)
p-type point contact (PPC)
Germanium detector (HPGe)
Institute for Nuclear Physics5 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
direct DM search with ultralow noise
ionization detectors – CoGeNT
PRL 101, 251301 (2008)
(i) a low-bg NaI[Tl] anti-Compton veto,
(ii) 5 cm of low-background lead,
(iii) 15 cm of standard lead,
(iv) 0.5 cm of borated neutron absorber,
(v) a >99:9% efficient muon veto,
(vi) 30 cm of polyethylene,
(vii) a low-effic. large-area external µ veto
exposure: 8.4kg.d
mc=8GeV, sSI=10-4pb
mc=6GeV, sSI=2x10-3pb
mc=4GeV, sSI=10-2pb
Institute for Nuclear Physics6 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
direct DM search – CoGeNT(2010)
light WIMP signal?
C. Aalseth etal., arXiv:1002.4703v1
mc=7(10)GeV, sSI=10-4pb440g PPC @Soudan (2100mwe)
with rise time discrimination
fast
(t=0.22µs)
slow
(t=1.53µs)
Institute for Nuclear Physics7 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
direct DM search – CoGeNT(2010)
light WIMP signal?
“…
In view of its apparent agreement with existing WIMP models,
a claim and a glimmer of dark matter detection in two other ex-
periments, it is tempting to consider a cosmological origin.
Prudence and past experience prompt us to continue
work to exhaust less exotic possibilities. We extend an
invitation to other researchers in this field to proceed
with the same caution. ...”
C. Aalseth etal., arXiv:1002.4703v1
Institute for Nuclear Physics8
WIMP
Heat
Ionization
Light
Ge, CF3I, C4F10
liquid Xe/Ar
NaI, liqu.Xe
Ge, Si
CaWO4, BGO
Al2O3, LiF
…via elastic scattering off nuclei
1% energyfastestno surface effects
10% energy
100% energyslowestcryogenics
WIMP
Target
Edelweiss,
CDMS
CRESST-2
Zeplin-3 , LUX,
Xenon-10/100
DAMA, Libra, Zeplin-1,
XMASS, KIMS, ANAIS
CRESST-1
HDMS
CoGeNT
COUPP
Picasso
WArP, ArDM
direct DM search – detection schemes
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Institute for Nuclear Physics9
direct DM search – using cryo-crystals
measuring principle:
c scattering with energy deposit ER leads to DT which can be read out
via thermometer detector with small V.CV needed
heat
ionization
Thermometer
Electrodes (charge
collection )
c
parameters for Ge bolometer:
E = 3V/cm
Top = 20mK
m = 300g (d=20mm; r=35mm)
VCV ~ 1nJ/K @ Top
G ~ 5nW/K thermal link to heat bath
Thermometer
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Institute for Nuclear Physics10
n/g discrimination
> 99.9%
for Er >15 keV
73Ge(n,n’g) 68.8 keV
13.3 keV
Ionization threshold
3.7 keV
Recoil threshold
20 keV
calibration of a 320g Ge bolometer with 252CfEDELWEISS@LSM
PRD 71, 122002 (2005)
direct DM search – n/g-discrimination
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Institute for Nuclear Physics11
direct DM search – Edelweiss @ LSM
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Institute for Nuclear Physics12
cryostat
Polyethelene
shieldPb shield
Muon Veto
Neutron
counter µ veto system
A=100m2 in
42 modules
direct DM search – Edelweiss @ LSM
2009/2010:
12 Ge bolometers
running
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Institute for Nuclear Physics13
features:
30 detectors
installed in 5 towers
4.75kg Ge & 1.1kg Si det´s
data taking since 10/2006
(>1000kg.d raw data)
1. data published in 2008 for 121.3kg.d eff. exposure
(arXiv:0802.3530v2 PRL.102:011301,2009)
Soudan Mine, Minnesota
direct DM search – CDMS @ Soudan
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Institute for Nuclear Physics14
direct DM search – n/g-discrimination
and surface events
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
surface bg source: leakage from
the g to the nuclear recoil bandPRD71, 122002 (2005)
Al 70nm
amGe 70nm
Ge 2cm
206Pba
e-
10keV - 100keV - 1MeV
Cu few mm
5 mm
~50 nm
350 nm
20 mm
700 mm
g 46 keV
3 mm
NO
ionisation
210Po 206Pb a
5.3 MeV100 keV
210Bi
e-1.16 MeV max
210Pbe-
61 keV max
g 46.5 keV (4%)
22 yr
Institute for Nuclear Physics15
… suppression via ionisation signal (Edelweiss-II):
interleaved electrodes (width: 200µm; gap 2mm)
Radius (cm)
Z (
cm
) guard ‘g’:
U=+1V
guard ‘h’: U=-1V
electron
trajectories
hole
trajectories
‘a&c’bulk event
‘a&b’ near-surface event
‘a,b&c’ event in low-field area
‘a’ electrodes: U=+2V ‘b’ electrodes: U=+1V
‘c’ electrodes:U=-2V ‘d’ electrodes: U=-1V
arXiv0905.0753
Phys.Lett. B681
(2009) 305
direct DM search – surface events
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Institute for Nuclear Physics16
… suppression via phonon signal (CDMS): effective and fast phonon
read-out (trise~5µs)
surface evts ≡ fast evts
ionis
ation y
ield
timing parameter [µs]
g´s/electrons
neutrons
surface evts
RoI
direct DM search – surface events
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Institute for Nuclear Physics17
Science 26March2010:1619
arXiv0912.3592 (612 kg.d raw data 2004-2009) PLB687 (2010) 294 (data 4/2009-9/2009)
(194.4 kg.d eff. Exposure, 10keV thresh.) (144 kg.d eff. Exposure, 20keV thresh.)
s(SI)<3.8 × 10−44 cm2 for m(c)= 70 GeV s(SI)<1.0 × 10−43 cm2 for m(c)= 80 GeV
direct DM search – results w/ Ge bolos
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
CDMS
Edelweiss
arXiv0912.0805
2 events survive
0.9 bg expected
1 event survives
0.23 bg expected
Institute for Nuclear Physics18 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
CDMS – next stepsSuperCDMS @ Soudan (funded)
March 19, 2009: warm up to install and commission first SuperCDMS detectors
Fabrication of detectors for SuperCDMS
Soudan (~13 kg Ge) project underway ~8000 kg.d
SuperCDMS SNOLAB (PASAG endorsed)
Project proposal in 2011 for ~100 kg Ge experiment
GEODM (NSF DUSEL “S4” funded)
GErmanium Observatory for Dark Matter (1.5 tons Ge)
proposed for Dusel
Ø=7.5cm,d=1cm (230g)
Ø=7.5cm,d=2.5cm (600g) new iZIP design
SuperCDMS detector
Institute for Nuclear Physics19 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
After fiducial selection
FID401210Pb source @LSM
before selection
ID400 (160g)
FID400>300g
FID800>600g
Goals: FIDs 400+800g program,
doubling of accum. exp. every year
2011 1000 kg.d exposure
2013 >3000 kg.d
Edelweiss – next steps >300kg.d data taken & prelim. analysed
Doubling/Quadrupling the fiducial
mass: ID400 => FID400 => FID800
4 running since July 27
Institute for Nuclear Physics20 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
direct DM search – scintillating bolos
300g scintillaing
CaWO4 crystal
W sensor
Light detector W sensor
Light reflector
(scintillating)
CRESST-2 at LNGS33 crystals installed
Phonon detector:
300 g cylindrical
CaWO4 crystal.
Evaporated tungsten
thermometer with
attached heater.
Light detector:
Ø=40 mm silicon on sapphire
wafer. Tungsten thermometer
with attached aluminum
phonon collectors and
thermal link.
Institute for Nuclear Physics21 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
direct DM search – scintillating bolos
CRESST-2 at LNGS
assumingσ ∝ A2
β+γ
α
OW
3 target nuclei within detector
3 quenching factors for
different nuclei
Institute for Nuclear Physics22 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
direct DM search – scintillating bolos
CRESST-2 at LNGS
γ + β band
α band
O-recoil-band
W-recoil-band
α
crystal
Pb
Pb α
clamp not scint.
210Po 206Pb (104 keV) + α (5.4 MeV)
2009/2010 data from 9 CaWO4
detectors (~400 kg.d; preliminary)
32 events in „O-band“
background estimate (mainly a):
8.7 ± 1.4
leaving space for a light WIMP m about 15 GeV or lessσ about a few times 10-5pb(W. Seidel, CRESST, idm2010)
Institute for Nuclear Physics23 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
direct DM search – results
Institute for Nuclear Physics24 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
direct DM search – scalar interaction?
Light neutralinos ??
Institute for Nuclear Physics25 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
T. Schwetz, IDM2010
direct DM search – hints for light c?
light neutralinos ?
-- hard to reconcile
compiling exptl. data
Institute for Nuclear Physics26 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
light neutralino within MSSM
tension from B tn, B Dtn,
Ft+t-, tbH+,
with CoGeNT&DAMA
would need non-MSSM DM
Kulik, Pierce, Zurek,
arXiv1003.0682
direct DM search – hints for light c?
5x10-42cm21x10-412x10-415x10-41
3x10-42
Institute for Nuclear Physics27 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Kopp, Schwetz, Zupan, arXiv0912.4264
direct DM search
– elastic spin-dependent scattering?
ap=1, an=0 ap=0, an=1
90% C.L. 90% C.L.
Institute for Nuclear Physics28 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Tucker-Smith, Weiner, hep-ph/0101138
direct DM search – iDM ?
inelastic scattering
must be favoured over
elastic scattering
could be naturally
explained via dark
gauge forces (Bjorken)
Institute for Nuclear Physics29
direct DM search – iDM ?
– DAMA excluded by CRESST
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Institute for Nuclear Physics30 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
indirect DM search – e+/(e+ e-) excess
can be explained
by nearby
astrophysical
sources
space for
DM signal?
Institute for Nuclear Physics31 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
indirect DM search (high-E solar n´s)
IceCube, PRL102,201302(2009)
Institute for Nuclear Physics32 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
future: increase target mass
~2013-2018
Institute for Nuclear Physics33
future: EURECA
EURECA goal: beyond 10-10 pb, 500 kg to
1 tonne cryogenic experiment, multi-target
“Generation 2” project with major efforts in
background control, detector development,
infrastructure
Joint European collaboration of teams from
EDELWEISS, CRESST, ROSEBUD,
CERN, +others…
Part of ASPERA European Roadmap
Preferred site: 60 000 m2 ULISSE
extension of present LSM (4 m/m2/d),
to be excavated in 2011-2012
Collaboration agreement with SuperCDMS
& GeoDM for common studies
MoU between EURECA, SuperCDMS and
GEODM collaborations:
http://www.eureca.ox.ac.uk/
Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
Sep 2009
Institute for Nuclear Physics34 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
future: XENON1T & DARWIN
XENON1T : construction 2011 DARWIN:
start of measurements 2013 DARk matter WImp search with Noble liquids
R&D and design study for next-generation
noble liquid facility in Europe
first ASPERA (AStroParticle ERAnet) in 2009
focus: coordinate existing European activities in
liquid argon and xenon towards the construction
of a multi ton
DM facility
physics goal:
probe s(SI)
well below
10-47 cm2
many more
projects
worldwide!!
Institute for Nuclear Physics35 Klaus Eitel | BOSEN workshop | 29 August – 3 September 2010
outlook
New projects Xenon1t, EURECA, SNOLAB, Kamioka, AMS-02, Planck,
Gravitational lensing, LHC
But lessons learned: Be careful with data interpretation!!!
personal: stay conservative, but open-minded
Interaction between different
communities needed, e.g.
Astroparticle, astronomy,
cosmology, collider,
fixed-target,
SUSY,
theory BSM...