G. Gerbier TAUP03-Seattle-6 /09/2003 1

Looking for SUSY…

G. GerbierCEA/Saclay, DAPNIA

Fréjus Laboratory, CEA/CNRS

with

- Status- Prospects Edelweiss I

Edelweiss II

G. Gerbier TAUP03-Seattle-6 /09/2003 2

-EDELWEISS Collaboration -CEA-Saclay DAPNIA and DRECAMCRTBT GrenobleCSNSM OrsayIAP ParisIPN LyonFZ-Karlsruhe and Univ. Karlsruhe Exp intalled in Modane Underground Laboratory (Fréjus Lab)

4800 mwe, 1700 m of rock- m flux = 4/m2/d- neutron flux = 1.6 10-6/s/cm2

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1kg stage of EDELWEISS I : 3 * 320 g Ge.•• GGA1: GGA1: heat and heat and ionisation ionisation Ge Ge 320320gram dgram detector etector , 20 mm , 20 mm thickthick•• Aluminium Aluminium electrodes (electrodes (center +center +gguard uard ringring)) + + Ge Ge aamorphous morphous layerlayer((built built by Canberra/by Canberra/EurysisEurysis))•• NTD NTD sensor glued sensor glued on on guard guard ringringelectrode electrode + + wiring wiring in Saclayin Saclay•• ««All All numericalnumerical!!»» acquisition acquisition•• L Low ow radioactivity radioactivity cryostatcryostat•• ShieldShield: 30 cm : 30 cm paraffinparaffin, 20 cm Pb, 10, 20 cm Pb, 10cm cm CuCu

•• Resolutions Resolutions @ 10 @ 10 keV keV ((resp resp 122) 122) keVkeV::•• ionisation ionisation : 1.3 : 1.3 keVkeV (2.2 (2.2 keVkeV))•• heat heat : : 1.0 1.0 keVkeV (3.0 (3.0 keVkeV))

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Close shield in Roman Pb1st data taking: Fall 2000, 1 detector mounted and used2nd data taking : First semester 2002, 1 detector used out of 33rd data taking : October 2002 - March 2003, 3 detectors used

ArcheologicalArcheologicalleadlead

3 * 320 g Ge detectors3 * 320 g Ge detectors

May 2002May 2002GGA1,GeAl9,GeAl10GGA1,GeAl9,GeAl10October 2002October 2002GGA3, GSA1, GSA3GGA3, GSA1, GSA3

1kg stage of EDELWEISS I : 3 * 320 g Ge.

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Am-Be neutronsource in situ

73Ge(n,n’g)

Ionization threshold3.7 keV

Recoil threshold20 keV

Q=

Neutron calibration

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GSA1 gamma calibration

Q=

g-ray rejection >≈ 99.99 % =>

run started after extendedgamma-ray detector exposure

Calib run equivalent to 60days running time w/outsource <=> 9 kg.d exposure

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EDELWEISS-I latest resultsoct 2002 – may 2003

• Additional 20 kg ¥ day fiducial exposure with 3 detectors

• Two events compatible with nuclear recoils– recorded during short noisy period

• Present total exposure: 13.8 kg ¥ day @ Erec">"20 keV, 30.5 kg ¥ day @ Erec">"30 keV

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Bolometer-1: Q = f(Er) diagram

Noisy period "?

The 4 events in red (1inside and 3 outside theneutron zone) all arrivedwithin an interval of afew days out of 90 daystotal acq time

-Exposure:7.51 kg ¥day (fiducial)-Best charge channel100 % e at 20 keV

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Bolometer-3: Q = f(Er) diagram

-Exposure: 10.85 kg ¥day fiducial

-Excellent phononchannel: 300 eV FWHMresolution during mostof the runs, noisy chargechannel

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How well do we measurerecoil energy ? «"Heat Quenching factor"»

- We assume above that energy measuredfrom heat signal is total deposited energyi.e. Eh electron = Eh nucl rec i.e. Qh =1 . Is that true ?

-Take Qh =0.95 and check what becomesquenching factor Qi curve

-Compare with data from litteraturefiQh is 1 +- 0.05fiEtot known within 5 %

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0.15

0.2

0.25

0.3

0.35

0.4

20 40 60 80 100

Quenching factor summary on Ge

Q(Lindhard)Q(Chas)Q(Shu)Q(Messous)Q(fit)

Que

nchi

ng f

acto

r

Recoil energy (keV)

=> Measur. of Qh can be sone of order 1 +- .05 from present analysis : in progress

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WIMP s vs M exclusion diagram

• Keep 2 evts as potential signaland set upper limits on WIMPsignal

• Correct for :– Fiducial volume (known 5 %)– Efficiencies : nucl. rec, fraction

of Wimp signal kept• Trigger eff. =100 % > threshold• No background subtraction• Same conventional halo, nucl.

phys. parameters as DAMA• Excludes DAMA candidate at

99.8% C.L.• Compatibility with DAMA ?

– Copi and Krauss": (Phys.Rev. D67(2003) 103507) exclusion is modelindependent

– DAMA data internal consistency? CDMSZEPLIN Prel

EDELWEISS

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DAMA : Questions of rate budget, PSD analysis

The detected signal is the modulated part Sm = 0.02 evts/kg/d => total WIMP signal S0 (2-6 keV) is-no constaint from NaI0 = 0.86 evts/kg/d-wth constaint from NaI0 =0.54 evts/kg/d

0.02-0.025 mod signal0.5 0.2 0.1 0.03 bulk signal nucl recoils1.0 1.8 1.8 1.7 total rate0.5 1.6 1.6 1.6 em backg

DAMA Phys Lett B 480 (2000) 23

Annual Modulation is < 7 % of unmodulated partfiUnmodulated «!bulk!» > 0.02/ 7 % = 0.3-0.5 cpd/kg/kevDependent only on relative velocities of earth/sun: knownShape is given by WIMP velocity:known (even if directional)

=>2 implicationsfiem background has rising shape (even 0 in 2-3 keV in cryst. 8)fiPSD, but much more efficient in 4-6 keV, expect a 8 s effect in 100 000 kg.d if pure stat( too small discr. in 2-4 keV)

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EDELWEISS": what’s next"?• New run started with improved energy threshold with

≈100% detection efficiency at 15 keV recoil energy(phonon trigger)

• In hand further additional 20 kg.d analysis in progress• But close to exp level of neutron background (1 evt/60 kg.d)

• December 2003 : end EDELWEISS-I run

• Jan-Dec 2004 : install EDELWEISS-II with– 21 ¥ 320 g Ge-NTD detectors and– 7 «!thin film!» 200 g Ge detectors : 9 kg

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EDELWEISS-II detector setup(Phase 28 detectors - 8 kg- in preparation )

- 100 liter cryostat for up to120 detectors : ≈ 36 kg Ge

- Development of Nb Si thin filmsensors to eliminate surfaceevents

- Clean crystal manufacturing- Clean room + radon reducedatmosphere ~ 0.1 Bq/m3

- Improve sensitivity by ≈!100

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New 100-liter dilution cryostat :8-10 mK obtained during several runsWiring and cold electronic test : summer 2003

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Experimental aims andtheoretical predictions

L. Rozkowski et al.,hep-ph/0208069

EDELWEISS-II sensitivity goal

1 Ton sensitivity goal (optimistic)

EDELWEISS-I present

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Conclusions

• Exclusion diagram of 2002 confirmed by 2003 data• EDELWEISS sensitive to -optimistic- SUSY models (≈10-6

pbarn)• EDELWEISS-II should be ready by 2005 to get factor ≈100

improvement in sensitivity (down to few 10-8 pbarn) andbegin to test more favored models (like CDMS-II, CRESST-II, ZEPLIN-II and -III)

• Testing the bulk of SUSY parameter space(down to 10-10 pbarn) will require experiments in the one-tonrange and extreme background rejection

• European supported programs will start soon