Technologies and results of direct dark-matter searches15 and 21/01/2016

Teresa Marrodan Undagoitia

• Program:

– Scintillator crystals

– Germanium detectors

– Cryogenic bolometers

– Liquid noble-gas detectors

– Superheated fluids

– Directional searches

• Literature:

– R. Bernabei et al. (DAMA Collaboration), Final model independent result of DAMA/LIBRAphase1, Eur. Phys. J. C 73 (2013) 2648, arXiv:1308.5109

– S. Ahlen et al., Limits on Cold Dark Matter Candidates from an Ultra low Background Ger-manium Spectrometer, Phys. Lett. B195 (1987) 603.

– N. Booth et al., Low-temperature particle detectors, A. Rev. Nucl. Part. Sci. 46 (1996) 471

– R. Agnese et al. (CDMS Collaboration), Silicon Detector Dark Matter Results from the FinalExposure of CDMS II, Phys. Rev. Lett. 111 (2013) 251301, arXiv:1304.4279.

– R. Agnese et al. (SuperCDMS Collaboration), Search for Low-Mass Weakly InteractingMassive Particles with SuperCDMS, Phys. Rev. Lett. 112 (2014) 241302

– G. Angloher et al., (CRESST-II Collaboration), Results on low mass WIMPs using an up-graded CRESST-II detector, Eur. Phys. J. C 74 (2014) 3184

– E. Aprile and T. Doke, Liquid xenon detectors for particle physics and astrophysics, Rev.Mod. Phys.82 (2010) 2053, arXiv: 0910.4956

– D.S. Akerib et al. (LUX Collaboration), Improved WIMP scattering limits from the LUXexperiment, arXiv:1512.03506

– E. Aprile et al. (XENON100 Collaboration), Dark Matter Results from 225 Live Days ofXENON100 Data, Phys. Rev. Lett. 109 (2012) 181301, arXiv:1207.5988

– E. Behnke et al. (COUPP Collaboration), First dark matter search results from a 4-kg CF3Ibubble chamber operated in a deep underground site, Phys. Rev. D 86 (2012) 052001

– C. Amole et al. (PICO Collaboration), Dark Matter Search Results from the PICO-60 CF3IBubble Chamber, arXiv:1510.07754

– J. Billard et al., Directional detection as a strategy to discover Galactic dark matter, Phys. Lett.B 691 (2010) 156.

– G Sciolla and C J Martoff, Gaseous dark matter detectors, New J. Phys. 11 (2009) 105018.

• Material for the lecture:

Figure 1: Residual rate of single-hit scintillation events by the DAMA/LIBRA experiment in the(2−6) keV energy region as a function of time. A sinusoidal function fitting the data is also shown.Figure from DAMA Coll., Eur. Phys. J. C 56 (2008) 333.

Figure 2: Energy distribution of the modulated component (Sm) for 1.33 ton×y exposure. Figurefrom DAMA Coll., Eur. Phys. J. C 73 (2013) 2648.

LNe LAr LXeZ (A) 10 (20) 18 (40) 54 (131)

Density [g/cm3] 1.2 1.4 3.0Scintillation λ 78 nm 125 nm 178 nm

Boiling point [K] at 1 atm 27 87 165Ionization [e−/keV] 46 42 64Scintillation [γ/keV] 7 40 46

Table 1: Summary of liquid neon (LNe), liquid argon (LAr) and liquid xenon (LXe) properties.

Figure 3: Schematic representation of the detection principle for cryogenic bolometers (left). Fig-ure from arXiv:1509.08767. (Right) Discrimination parameters for the CDMS detector: ionisationyield and timing parameter for electronic recoils, nuclear recoils and surface events. Figure fromCDMS Collaboration, Phys. Rev. Lett. 102 (2009) 011301.

Figure 4: (Left) Scheme of the interleaved electrodes to reduce surface events in the Edelweiss-IIIdetector design. Figure from Edelweiss presentations. (Right) CRESST results (red) on low WIMPmasses. Figure from CRESST-II Collaboration, Eur. Phys. J. C 74 (2014) 3184.

Figure 5: (Left) Ionization yield in all detectors used in the silicon analysis of CDMS. The top panelis before photon timing cut and the bottom one is afterwards. Figure from CDMS Coll., Phys. Rev.Lett. 111 (2013) 251301. (Right) Light yield for one CRESST detector module. The region used forthe dark matter search is marked in orange. Figure from CRESST Coll., Eur. Phys. J. C 72 (2012)1971.

Figure 6: Schematics of liquid noble-gas detectors: single phase (left) and double phase TPC(right). Figures from arXiv:1509.08767.

Figure 7: (Left) Modulation study in XENON100: −2 log(L0/L1) as a function of period being thephase unconstrained. (Right top) Monte Carlo simulation of the expected mean and 1σ regionsfor a modulation signal with periods of 100, 365 and 500 days. (Right bottom) Best XENON100 fitresult for a period fixed to 1 year compared to the expectation based on the DAMA signal. Figuresfrom XENON Coll., PRL 115 (2015) 091302 and arXiv:1507.07748.

Figure 8: (Left) Comparison of the DAMA/LIBRA modulated rate in the (2− 6) keV energy rangeto the background rate of the XENON100 experiment. (Right) DAMA/LIBRA modulated spec-trum (red) interpreted as WIMP scattering through axial-vector interactions as it would be seen inthe XENON100 detector. XENON100 spectrum is also shown (blue). Figures from XENON Coll.,Science 349 (2015) 6250, 851 and arXiv:1507.07747.

Figure 9: (Left) Charge over light ratio as function of the nuclear recoil energy for calibration datausing gamma sources (blue) and nuclear recoils (red). Figure from the XENON collaboration.(Right) Distribution of nuclear recoils (blue) and alpha events (red) in an acoustic parameter, APin the COUPP experiment. Figure from COUPP Coll., Phys. Rev. D 86 (2012) 052001.

Figure 10: Events in a superheated-liquid bubble chamber of 1.5 kg mass of CF3I. A: muon trackat ∼ 60◦, B: nuclear recoils from neutrons at ∼ 30◦, C: expected signature of a WIMP interaction, asingle nuclear recoil bubble. Figure from E. Behnke et al., Science 319 (2008) 933.

Figure 11: Schematic representation of the detection principle for cryogenic bolometers (left) andfor directional detectors (right). Figure from arXiv:1509.08767.

]2WIMP mass [GeV/c1 10

]2W

IMP

-nuc

leon

cro

ss s

ectio

n [c

m

-4310

-4210

-4110

-4010

-3910

-3810

DAMA/I

DAMA/Na

CoGeNT (2012)

CDMS+EDELWEISS (2011/12)

XENON10 (2013)

LUX (2015)SuperCDMS (2014)

DAMIC (2012)CRESST (2015)

CDMSlite (2015)

CDMS-Si (2013)

EDELWEISS (2015)

]2WIMP mass [GeV/c10 210 310

]2W

IMP-

nucl

eon

cros

s se

ctio

n [c

m

-4510

-4410

-4310

-4210

-4110

-4010

DAMA/I

CDMS+EDELWEISS (2011/12)

XENON100 (2012)LUX (2015)

Dark Side (2014)

PICO-60 (2015)

PandaX (2014)

DAMA/Na

Figure 12: Results for spin-independent cross section. Figures updated from arXiv:1509.08767.

]2WIMP mass [GeV/c10 210 310

]2S

pin-

depe

nden

t WIM

P-ne

utro

n cr

oss

sect

ion

[cm

-4010

-3910

-3810

-3710

-3610

-3510

-3410

XENON100 (2013)

CDMS-II (2009)

ZEPLIN-III (2009)

DAMA (2008)

]2WIMP mass [GeV/c10 210 310

]2Sp

in-d

epen

dent

WIM

P-pr

oton

cro

ss s

ecti

on [

cm

-3910

-3810

-3710

-3610

-3510

-3410

KIMS (2011)

PICASSO (2012)

SIMPLE (2011)

XENON100 (2013)

COUPP (2012)

PICO-2L (2015) PICO-60 (2015)

DRIFT (2015)CDMS-II (

2009)

DAMA (2008)

Figure 13: Current results for spin-dependent cross section. Figures updated fromarXiv:1509.08767.