dark matter -- astrophysical evidences and terrestrial ...€¦ · geodm (nsf dusel “s4”...

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


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)


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


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)


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


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



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



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



direct DM search – Edelweiss @ LSM



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



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



direct DM search – n/g-discrimination

and surface events


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


… 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



… 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



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


CDMS

Edelweiss

arXiv0912.0805

2 events survive

0.9 bg expected

1 event survives

0.23 bg expected


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


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


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.



CRESST-2 at LNGS

assumingσ ∝ A2

β+γ

α

OW

3 target nuclei within detector

3 quenching factors for

different nuclei



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)


direct DM search – results


direct DM search – scalar interaction?

Light neutralinos ??


T. Schwetz, IDM2010

direct DM search – hints for light c?

light neutralinos ?

-- hard to reconcile

compiling exptl. data


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


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.


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)


direct DM search – iDM ?

– DAMA excluded by CRESST



indirect DM search – e+/(e+ e-) excess

can be explained

by nearby

astrophysical

sources

space for

DM signal?


indirect DM search (high-E solar n´s)

IceCube, PRL102,201302(2009)


future: increase target mass

~2013-2018


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/


Sep 2009


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!!


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...

dark matter -- astrophysical evidences and terrestrial ...€¦ · geodm (nsf dusel “s4”...

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