PoS(EPS-HEP 2009)009 http://pos.sissa.it/ ]. Moreover, both theory and observations point 3 , 2 , 1 ∗ [email protected] Speaker. An increasing number of astronomicalUniverse and is astrophysical composed observations strongly of suggest moreinvisible that matter than the has 96% to of bereferred invisible non-luminous, to non-baryonic matter as and and Cold cold energy Dark (i.e. Matter andto (CDM) the non that fact [ relativistic), that most therefore CDM of is constitutedCDM the neither particle by is baryons the nor so by called neutrinos.WIMPs Weakly Interacting The detection Massive leading is Particle candidate to (WIMP). as A measure direct thenuclei approach of nuclear to target recoils materials in produced detectors in placed deep theused underground. scattering in A Dark of review Matter of WIMPS direct the off detection main technologies experiments the isbased presented, on with cryogenic a special noble focus liquids on as experiments target and detectors. ∗ Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. c

European Physical Society Europhysics Conference onJuly High 16 Energy - , 22 EPS-HEP 2009 2009, Krakow, Poland Elena Aprile Direct searches for Physics Department, , 538 WE-mail: 120 St New York , NY 10027 PoS(EPS-HEP 2009)009 ]. 4 [ (2.1) , and cross is the , large R 1 , where > − 1 s − v is the mo- s 2 a 3 Elena Aprile R − > σ can be easily v E cm a N R 27 σ < cm − . Therefore one < E m 5 v 10 2 · non-baryonic ], and, though they 3 or, at least, have an √ 6 ' = weak interaction | χ q n c ~ | χ ρ stable : m θ = 2 , h ]. This means that these particles and the velocity ) 5 χ θ a Ω σ cos . Moreover, anisotropies in the Cosmic 1 − − 1 s ( 3 i.e. non-relativistic. Finally, considering the 2 v , very close to a typical cm N N 1 − − 25 m 2 is the present number density and 2 χ cold s − 3 µ χ is non-relativistic, the recoil energy n 10 cm v = ∼ 25 N 2 | − > m q ~ | v 2 10 a is the WIMP-nucleus reduced mass. The differential nuclear σ ÷ = N ]. Thus, direct Dark Matter search experiments aim to detect N m R 26 7 < m + χ E − χ m m 10 = ∼ N > − v χ a µ σ < nucleon relative velocity are the masses of the target nucleus and of the WIMP, from the Big Bang, and their abundance is − χ m relic , of the induced nuclear recoils and possibly, in directional experiments, the direction. and R 3, they had to have decoupled before the present time [ N E . 0 m The most important contribution to the matter content of the Universe is in Dark Matter, whose According to this picture, Dark Matter provides the first empirical evidence for particles be- If WIMPs exist, they are also the dominant mass in our own Milky Way [ ∼ = is the mass of the Dark Matter particles, M χ where mentum transfer and Since the WIMP only very rarely interact with conventionalsensitive matter, detectors should on nonetheless Earth. be The detectable WIMP byenough flux sufficiently on to Earth allow should be the ofnuclei detection the order of of of Earth 10 the based nuclearthe detectors recoils interactions [ caused of by WIMPs their inenergy, dedicated elastic low scattering background off detectors, target by measuring the rate, expressed in terms of the scattering angle in the center of mass frame, present conditions of the Universe, the Dark Matter particles have to be In the framework of theof the Big Universe, Bang the theory, Dark itin Matter is order particles to natural were provide in to the thermal assume presentΩ equilibrium significant that with abundance during the and the to others. satisfy earlyrepresent However, the moments a cosmological requirements obtains a value for section, which is of theMicrowave order Background of radiation (CMB), createdsity, by are the not enough fluctuations to in create the thewould distribution baryonic not of be matter matter able den- of to the assemble presentpuzzle into Universe is the and that hot large Dark scale Dark Matter structure Matter we particles see have today. The to only be solution to this nature is still unknown. Onenomical can scales speculate about with its the features principlesosynthesis combining of we observations the on know all Standard that astro- Cosmological the Model. majority of From the Big missing Bang mass nucle- in the Universe is yond the Standard Model ofof particle the physics. generic On Weakly the Interacting othermetric Massive hand, extensions Particles particles of or the with WIMPs, Standard the Model, are characteristics An with predicted example largely in and different a many mass favorite and supersym- WIMP interaction candidate cross-section. is the , the lightest supersymmetric2. particle. Dark Matter direct detection Direct searches for Dark Matter 1. Introduction m thermal average of the product of annihilation cross-section average lifetime longer than the age of the Universe. PoS(EPS-HEP 2009)009 , 2 ), is A 2 A esc (2.2) ∝ v σ and is the cross Elena Aprile R 0 E σ and in the dark matter ) v Total event rate (dashed ( f . As the atomic mass num- 2 . enhancement. However, neu- 2 cm dv ) v 45 ( − v f Figure 1: curves) for WIMP elasticxenon, germanium scattering and off targets, cal- culated for a WIMP mass ofand 100 GeV/c a WIMP-nucleus10 cross section of ber increases, the rateenergies, due increases to at the coherence low while ( as the recoil energythe increases (i.e. de Brogliethe wavelength nuclear approaches dimensions)creases, due the to rateinfluence the of de- form the factor.pronounced for form high The factor massments. is number A ele- low more energyfore threshold is mandatory there- for detectorsmass number with targets. high esc v min , for a target nucleus of mass number v 2 Z A ) R ∝ E is the local dark matter density, 0 ( 0 2 σ ρ 3 F χ 0 . A possible WIMP direct detection with directional m σ 0 0 N ρ is the WIMP velocity distribution in the galactic halo, ρ m ) R v for ( f 3 dE is the nuclear form factor, which accounts for the fact that the − th ∞ ) E R Z cm . A common assumption is to use a Maxwellian distribution for E 2 ( 0 = 2 − ρ F R is the energy threshold of the detector, is the minimum velocity required for the WIMP to generate the recoil energy th E and a value of 0.3 GeVc = As a result of the Earth motion relative to the WIMP halo, the event rate is expected to modu- The main astrophysical uncertainties lie in the velocity distribution If WIMPs are , i.e. Majorana fermions, they can have only scalar or axial coupling ) in v ( m f late with a period of one year with the maximum on the 2nd of June. To detect this characteristic Here tralinos with dominantly gaugino orterm. higgsino states may only couple through the spin-dependent with quarks, which, in this specificpling non-relativistic and regime, a translates into coupling a betweencase, spin-independent the the cou- full neutralino coherence spin results and in the a nucleon cross section spin. In the spin-independent section at zero momentumv transfer, the galactic escape velocity. de Broglie wavelength associated with thedimensions; thus momentum the transfer bigger is the of nucleus the the same stronger order this as effect becomes. the nuclear density in the Earth vicinity, experiments would provide a viable solution to the velocity distribution function problem. while in the spin-dependent case theIn cross most section cases, is dominated the by coherent the term total will net dominate spin because of it the has nucleus. the A Direct searches for Dark Matter recoil rate induced by the WIMPs can be written as follows: PoS(EPS-HEP 2009)009 Elena Aprile 2% with respect ∼ ]. The project was designed in the1990 10 4 event per day per kg. Exploring this parameter space 6 − . In addition, the detectors are typically enclosed by thick layers ’s and hydrogen-rich compounds for neutrons), in order to reduce 7 γ to 10 5 ] the expected WIMP rate is less than 0.1 event per day per kg and significant 9 , 8 -ray or a neutron is of the order of centimeters, the mean free path of a WIMP is γ A large number of experiments aiming at a direct detection of Dark Matter are deployed in The DAMA/LIBRA experiment is presented as it is the only experiment which has to-date Dark matter search experiments are located in deep-underground sites, to attenuate the cosmic A stronger diurnal direction modulation of the WIMP signal is also expected. TheNuclear Earth recoils induced by WIMPs are detected exploiting the three basic phenomena associ- by an Italian groupwas and initially installed based at on nine Gran 9.7background. Sasso kg highly underground The radio-pure laboratory. NaI(Tl) collaboration scintillators The has shielded detector then from radioactive (DAMA) upgraded the detector to a sensitive mass of 250 kg of of the order of ais light-year, possible given to its reject extremely low thoseminimal coupling events time that with window have ordinary more between matter. than two Inactive one consecutive this veto. interaction events way, in or it However the packing an detector thedimensional efficient by position sensible identification reconstruction defining volume of a method within the of event’s an signatureachieve the in a the good events detector) rejection (generally is power. necessary based Finally in indiscrimination on order mechanisms many to three- are dark used, matter based direct on search the experimentselectron fact background that recoils nuclear recoils (induced (induced by by WIMPs) thedue and background to the particles) different generate nature different of signals the particles. in the detectors, 3. Dark Matter direct detection experiments (a selection) underground laboratories all around theselection of world. them is Several presented are in this in review. construction phase.3.1 Only The DAMA/LIBRA a Experiment small claimed a positive detection of Dark Matter WIMPs [ also the contribution due tofor the all these environmental experiments, radioactivity. is in A theallow key screening significant requirement, and background selection and reduction. of a Detectors shielding which challenge andin the detector the identification components, target to of multiple volume interactions providesa a high powerful energy rejection method. Indeed, while the mean free path of muons flux by a factor 10 requires ton-scale detectors with nearly vanishing backgrounds. of absorbing materials (lead for SUSY parameter space exists down to 10 rotation about its axis,direction oriented by at 90 angle degrees with everyrate. 12 respect hours, to with the a WIMP resulting “wind”, 30% changes modulation on theated respect signal with the to energy the loss of total the charged particles detectors used in to target perform media: this scintillation, rareassociated ionization event and with search heat. are cosmic also All rays sensitive to andthe the current radioactivity environmental limits radiation in [ construction materials and the environment. At Direct searches for Dark Matter modulation signature, large masses are required, sinceto the the effect is total of event the rate. order of PoS(EPS-HEP 2009)009 year), × yr) × Elena Aprile Time (day) (target mass = 232.8 kg) DAMA/LIBRA (0.53 ton 22 days. ± rejection power). All other background 10 10 > equal to 140 5 2-4 keV 0 t 5 keV. Precautions are being taken in order to re- particles from natural occurring radioactive isotopes, yr) ∼ × s) are well below the nucleation threshold. The energy α C.L annual modulation signal in WIMP-proton elastic I was operated at the Fermilab NuMI underground tun- β 3 σ 3 . left. Such small detector provided the most stringent limit on 3 01 year and offset m (like scattered nuclei) can create a bubble nucleation, the detector . (target mass = 87.3 kg) 0 DAMA/NaI (0.29 ton µ ± -rays, X-rays and 00 . γ ) where the understanding of the efficiencies is particularly important. The 50 keV/ 2 > Rn and its daughters. dx 222 /

year.

dE DAMA annual modulation signal from a model independent fit to the cosine function, showing a × (cpd/kg/keV) Residuals 300 meters water equivalent). Few examples of different type of events detected by this ∼ The COUPP (Chicagoland Observatory for Underground ) experiment exploits A first prototype with 1.5 kg of CF The DAMA experiment belongs to the first generation of dark matter direct detection exper- The DAMA/LIBRA evidence for the annual modulation is clear but only in the lowest energy nel ( prototype are shown in Figure is extremely insensitive to electron recoil events ( threshold for recoiling nuclei is as low as mainly from the bubble chamber technology.cles By with tuning the superheated liquid in such a way that only parti- origin of this clear modulation and itsstudies interpretation have continue been to performed be by widely the disputed, collaboration although regarding many various possible systematic effects. 3.2 The COUPP Experiment particles (like muons, duce the inhomogeneous bubble nucleation bybackground mildly in superheating the the COUPP liquid. detector are A the notable source of Figure 2: period of oscillation of 1 iments, which require a largediscrimination detector between exposure. nuclear recoils Although and the electronpublished recoils NaI(Tl) its based scintillator data on without provides pulse any background some shape, reduction. the Using collaboration a seven-year exposure (0.29 ton Direct searches for Dark Matter NaI(Tl). This new experiment, called LIBRA, isfor running since both March experiments 2003. is The 2 threshold keV. provided the DAMA collaboration reported ascattering. 6 Recently, the LIBRA0.53 experiment ton has confirmed the observation with an exposure of bins (2-6 keV correspondingnuclei, to see a Figure nuclear recoil energy of 22-66 keV for interaction on Iodine PoS(EPS-HEP 2009)009 30 ∼ Elena Aprile ], the XENON 12 , 9 (right)). 3 . The inner TPC target 6 ], excluding the low mass region 11 6 . 4 for the WIMP-nucleus spin-independent cross section at a WIMP mass of I COUPP detector has been constructed, and will likely operate at SNOLAB. 3 2 cm 45 (left) examples of different type of particles detected at different temperature and pressure con- − , as shown in Figure 2 10 A schematic view of the XENON100 detector is shown in Figure A 60 kg CF Of the several direct detection experiments based cryogenic noble liquids, currently only two × 2 GeV/c collaboration has designed andfactor built 10 a and second a generation background∼ experiment reduction with of a a mass factor 100, increase in of order a to achieve the sensitivity goal of favored by a spin-dependent interpretation of the DAMA signal (see Figure is surrounded by anwalled active vacuum liquid cryostat made veto. ofto low fill Both activity the stainless target detector steel andThe is (SS). veto light 170 The readout are kg, total is contained mass of based(Hamamatsu in of on which R8520-06-AL), a a Xe with approximately selected total required double- 65 low number radioactivity kg materials; ofhigher seventy are 242, quantum of in 1 such efficiency, PMTs inch the better have square fiducial than photomultiplier volume 30%. tubes (target). (PMTs) The target is seen by a top and a bottom array of Figure 3: 3.3 The XENON Experiment are operating underground:target XENON mass using on liquid the Xe 100technology, and with kg WARP simultaneous scale. using detection These of liquiddirect experiments the scintillation Ar, exploit ionization signals. both the (via The with time proportional amplitudeevent a localization scintillation) projection and capability, timing and chamber enables these of the (TPC) TPCs the toXENON signals, effectively identify collaboration as and is well reject following as background. a the The Xe, phased 3-dimensional with approach to a the series direct ofrealize detection within detectors the of of middle WIMPs of increasingly in next larger decade liquid to an mass search experiment and for with a WIMPs lower ton with background. scalelimit. almost fiducial After target four The (XENON1T) the orders goal successful of results is of magnitude to the better first sensitivity 10 kg than scale the prototype, current XENON10 [ best ditions in the 1.5 kgon COUPP the spin-dependent prototype (pure) operated proton-WIMP atCOUPP interaction the prototype. cross Fermilab section versus NuMI WIMP underground mass, tunnel. obtained with (right) the Limit Direct searches for Dark Matter pure proton spin-dependent interaction for low mass WIMPs [ PoS(EPS-HEP 2009)009 1 mm < Elena Aprile y plane and − XENON100 sensitivity as function of the Figure 5: exposure. 7 Schematic view of the XENON100 detector design. Figure 6: WIMP-nucleon cross-section upper limit Figure 4: (90 % C.L.)periments. from direct The dark projectedXENON phases upper matter are limits shown search as for dashed ex- lines. all the PMTs, as in XENON10. An importantthe background ability rejection to feature localize of events the in XENON100 detector 3-D is with a spatial resolution a few mm in x Direct searches for Dark Matter PoS(EPS-HEP 2009)009 ]. 14 Elena Aprile prototype [ l . It consists of an external 7 0.4 ms was achieved. Although ± ]. It is a new generation Dark Matter direct 13 8 Kr concentration below the 50 ppt (part per trillion) required liquid argon [ 85 l Kr in Xe. A cryogenic distillation column has been tested and op- 85 detector layout is schematically shown in Figure l s) components. In addition, and like the XENON100 experiment, WArP relies µ 1.4 ∼ of active LAr target), the active veto formed by about 8 ton of LAr around the inner detector l In addition to the background discrimination accomplished by the simultaneous detection of The WArP 100 The target is enclosed by a teflon structure, made with interlocking panels. Teflon is used as an For a TPC like XENON100, where the maximum drift length that ionization electrons have To reduce the radioactivity from the detector components and shield materials, a careful se- The commissioning of the XENON100 experiment is underway and calibration and first de- The WArP experiment is also based on a double-phase TPC technology. In this case the detection experiment, whose technology has been successfully tested with a 2.3 primary and secondary scintillationscintillation signal, signal a can suitable be used, pulsethe given shape the slow discrimination wide ( separation of in the rise primary time between the fast (5 ns) and on the power of theexperiment is 3-D located event at position the Gran reconstruction2009. Sasso for Laboratory. additional A background first calibration rejection. run was The carried out inpassive May shield (a polyethylene 70 cm thicka layer 15 as ton n-shield LAr and cryostat a (aand lead made double 10 of wall cm stainless thick cryogenic steel gamma-shield), selected vessel for insulated(100 low with radioactive contamination) vacuum containing and the inner super-insulation detector and, externally to the active veto, also immersed in LAr, a 10 cm thick shield of polyethylene. effective UV light reflector and astwo an in electrical insulator. the The liquid TPC and isthe two defined top in by the liquid four wire gas. one meshes, throughtwo The meshes, bottom 30 together liquid field with mesh shaping the acts rings,region. one as placed below cathode The at the and liquid is a wire level, connected mutual meshes“diving define to bell”, distance and the keeping of the gas top liquid 1 proportional PMT level at scintillation cm.by array a the precise are The gas height. mounted top returning A positive from in pressurea the in a high gas the temperature SS bell recirculation getter. is system, cylinder provided which closed continuously on purify top the Xe by through a to travel is 30 cm, anlow essential levels. requirement In is the the XENON10 reduction detector of an any electron electronegative lifetime impurity of at 1.8 very lection of all the materials hastivity been screening done. of This many was samples, performedSimilarly mainly based important performed on with in the High terms results Purity of ofcontamination Germanium radioactivity the of spectrometers. contamination, radioac- radioactive is the requirement for very low level Direct searches for Dark Matter in z. more challenging, similar levels are being achieved in XENON100. erated on XENON100 to reduce the tector characterization have started. The2010. first scientific run is expected to start at the beginning3.4 of The WArP Experiment sensitive medium consists of 100 by the sensitivity goal. PoS(EPS-HEP 2009)009 Ar, but on Elena Aprile 40 chamber and projected Ar from l 39 Spin-independent WIMP-nucleon cross- Ar production induced by cosmic rays is 39 section upper limitsmass, (90 set by % the WArP 2.3 sensitivity C.L.) for the versus 100 l WIMP and 1 ton scale detectors. Figure 8: 9 Ar (565 keV endpoint, and half life-time of 260 yr) in natural 39 Ar in natural argon is 1 Bq/kg. Isotopic separation by centrifugation or 39 Ionization yield versus recoil energy for ]. The inner detector, equipped with field-shaping electrodes for the drift field, grids for extrac- The cosmogenic beta decaying 8 Figure 7: all the events passing the analysisin cuts [ as published tion of ionization electronsPMTs from for liquid the readout to of the thevolume gas light works signals, phase as is and suspended active proportional atthickness shield the of light (veto) center the production, of against active the and LAr gamma LAr shieldby veto and is PEEK volume. 60 neutron supports This cm. that backgrounds. are It’sof viewed connected the The by to active photomultipliers minimum shield a that volume. thin are Onlength copper held the structure shifting/reflecting in Cu that place layer structure delimits are (TetraPhenylButadiene the alsoreflective wavelength mounted external plastic shifter, the surface substrate). deposited basic A elements on total ofphotocathode of a the coverage 436 wave- of highly 3” the phototubes inner surface are and installedphotoelectrons). a in nominal The the threshold inner active of detector shield 10 keV and forof for 10% the events argon active occurring recoils shield in (10 the are central optically volume). separated (to avoid vetoing argon is unavoidable and is the limitingThe factor specific for the activity WArP of experiment for WIMP direct detection. differential thermal diffusion are establisheda techniques multi-ton for scale separation could of becomefrom extremely natural expensive gas and wells require isstrongly of a suppressed potential long underground. interest production because time. Argon Direct searches for Dark Matter PoS(EPS-HEP 2009)009 . 2 shows 9 Elena Aprile . ]. Figure 6 8 . The background, 11 for a WIMP mass of 60 GeV/c 2 cm multi wire TPC filled with 40 torr of 3 44 − 10 × 10 ), which is then read out. The other face of the detector, Ω m 10 ∼ , with a minimum of 6.6 10 ]. 15 , allows the collection of the charges using an electric field. The double detection Al (167 g) [ 2 CS The DRIFT-II experiment at the Bulby mine is a 1 m Gas based TPCs, where a recoil event with a few keV has detectable size trajectory in the There are several directional experiments under construction or already operating all around Due to the Sun’s motion around the galactic center, and its relative motion in the WIMP To detect WIMPs interactions, CDMS uses the so called ZIP (Z-dependent Ionization Phonon) Electron recoil events from surface contamination result in a reduced ionization signal, leading The data acquired between October 2006 and July 2007 with the complete detector have been • gas medium, can provide such directionalstopping power information. than The that fact of that nuclearsuring electron recoils both recoils allows the have a range smaller viable and background theexperiments rejection ionization. is method, the A by three-dimensional challenge mea- event for reconstruction. this type of Dark Matter directthe detection world, using different type of gas and different technologies for signal read-out: being uniformly distributed around the detectorcannot and mimic having such a WIMP characteristic directional isotropic signal, directionality, anddetection a result. total of 10 events is sufficient to claim a positive halo, WIMPs coming towards the Earthwind have comes to have from specific the directions.the Cygnus Knowing direction that constellation the of direction, WIMP possible a WIMP strong signals forward/backward is asymmetry in expected, as shown in Figure 3.6 Directional experiments covered by detector technology, consisting in disc-shaped germaniumfinal CDMS-II (250 experiment g) consists or of a silicon total (100 ofThe 30 g) technique detectors, crystals. allows 19 the Germanium The simultaneous and 11 detection Silicondisc of crystals. is ionization covered and by phonon a signals. thin layer Oneare of face evenly distributed aluminum of over and the the 1024 surface. tungsten The transition-edgethe Al sensors layer two (TES) provides materials, which the so phonon-phonon coupling that between thethe athermal Al phonons by can breaking pass Cooper thetransition pairs. interface temperature, depositing These and their pairs thus energy are a into change tunneled small in into variation the the in TES TES’s the resistance( at TES the temperature superconducting will cause atechnique significant provides both a high sensitivity and an efficient discrimination method. to the leakage of suchdeveloped by events into the the collaboration, nuclear providesresulting an recoil rejection effective power identification for discrimination region. the against electron these A recoil events background phonon and is timing of the cut, the orderanalyzed and of the 10 results published in 2008 for a total exposure of 121.3 kg-day [ Direct searches for Dark Matter 3.5 The CDMS experiment the event distribution inacceptance the regions ionization for yield the -The electron recoil upper recoil energy limit background parameter (at and space, 90CDMS the % which is C.L.) nuclear shown defines in on recoil the Figure the interesting spin-independent signals. WIMP-nucleus cross section reported by PoS(EPS-HEP 2009)009 Elena Aprile Spin-independent WIMP-nucleon Figure 10: cross-section upper limits (90 % C.L.) versus WIMP mass, set by the CDMS-II121.3 experiment kg-day. for a total of 11 . 1 − Ionization yield versus recoil energy for Example simulation of WIMP flux plotted in galactic coordinates for a Maxwell-Boltzmann halo 220 km s = 0 ]. v 8 Figure 9: all the events passing the analysisin cuts [ as published Figure 11: with Direct searches for Dark Matter PoS(EPS-HEP 2009)009 , 4 He 3 Elena Aprile TPC filled with 150 torr 3 , (Addisn-Wesley, U.S.). TPC filled with 50 torr of CF 3 (1990) 3565. m 41 (2009) 011301 [arXiv:0802.3530 2 − 102 pb level, as in some favored SUSY models, 8 − , 1433 (2003). 75 12 (1985) 3059. ]. 31 17 ]. (1992) 1552. 18 (2007) 728. The early Universe (Frontiers in Physics) 103 661 , L109 (2006). 648 [CDMS Collaboration], Phys. Rev. Lett. et al. , equipped with 3 x 3 cm Micromegas with pixellized anode, suitable both for energy and equipped with microwell for energy and three-dimensional event reconstruction 4 4 ]. 16 and event trajectory measurements [ and CF Finally, the MIMAC experiment at Saclay consistsy of several TPC modules filled with The DM-TPC experiment at MIT consists of two 10 The NEWAGE experiment at the Kamioka mine is a 23 x 28 x 30 cm of CF [ where the three-dimensional readoutprovided is by photomultipliers done [ with CCDs while the energy information is [astro-ph]]. Increasing mass while keep lowering backgrounds is the rule of the game and noble liquids The identity of Dark Matter particles still remains a mystery, but the potential for breakthrough • • • [5] M. S. Turner, E. W. Kolb, 1990, [1] W. Freedman and M. Turner, Rev. Mod. Phys., [2] D. Clowe et al., ApJ, [3] M. J. Jee et al., Astrophys.[4] J. K. Griest, M. Kamionkowski, and M. S. Turner, Phys. Rev. D [6] M. R. Merrifield, Astronom. J., [7] M. W. Goodman, E. Witten, Phys. Rev. D [8] Z. Ahmed [9] J. Angle et al. (XENON10 Collaboration), Phys. Rev. Lett. 100, 021303 (2008). continue to advance towardsfollow this quickly the goal. current generation Ton experiments.and scale A direct SD experiments detection interactions, signal, are needs from to technically either beof or feasible experiments validated both is SI with and therefore more will vital than for oneat this target good research and pace field. and concept: Directional will the experiments most current are probably also zoo provide advancing the ultimate “smoking gun”References for a DM signal. the experiment should start seeingimportant a is handful that of for WIMPannual the events modulation. first and time that a is very low exciting. background, massive Equally target, other than NaI, can probe in the coming decade isin very recent likely. years, driven Direct in detection partand experiments by collider have an searches. made aggressive significant Several competition 100 worldwide. progress kgunder They construction, scale complement promising experiments indirect interesting are new presently results in inare the operation expected coming underground in years. or 2010. For If XENON100, the results cross-section is at the 10 4. Summary Direct searches for Dark Matter PoS(EPS-HEP 2009)009 Elena Aprile (2005) 173. S. Burgos et al. (DRIFT (2008) 091301. 555 (2008) 333 101 56 13 (2009) 305 [arXiv:0906.3910 [physics.ins-det]]. . 608 , 265 (2005). (2007) 012012. 49 (2007), no. 4Ð5, 409. 65 28 (2008) 933; 319 http://warp.pv.infn.it Collaboration), Astropart. Phys. available at [16] T. Tanimori et al., Phys. Lett. B[17] 578 (2004) D. 241. Santos et al., J. Phys.[18] Conf. Ser. A. Roccaro et al., Nucl. Instrum. Meth. A Direct searches for Dark Matter [10] R. Bernabei et al. (DAMA Collaboration), Eur. Phys. J. C [15] G. J. Alner et al. (DRIFT Collaboration), Nucl. Instr. Meth A [11] E. Behnke et al., Science [12] J. Angle et al. (XENON10 Collaboration),[13] Phys. Rev. Lett. R. Brunetti et al., WARP: WIMP Argon Programme, Proposal for WARP to[14] INFN, March R. 2004, Brunetti et al., New Astron. Rev.