DAMA, CoGeNT, CRESST, CDMS, EDELWEISS, XENON Rafael F. Lang Tuchan Purdue University [email protected] MPI Heidelberg, January 2012 picture: Thomaspicture: 1 Most Matter is Dark Matter from • Big Bang nucleosynthesis • cosmic microwave background fraction baryon BBN D • structure formation BBN 3He SDSS5 • galaxy clusters WMAP5 • rotation curves of galaxies matter density • … we know: most of the matter in the Universe is not Baryons, but some new stuff arXiv:1001.4744 Rafael F. Lang: How to Fish for WIMPs 2 How to Search a Thermal Relic • Production Collider Searches • Annihilation Indirect Searches Rafael F. Lang: How to Fish for WIMPs 3 How to Search a Thermal Relic • Production Collider Searches • Annihilation Indirect Searches • Scattering Direct Searches Rafael F. Lang: How to Fish for WIMPs 4 physics (MSSM showupetc.) (MSSM to physics the new expect where we usualwouldis this Expectationsin Rafael F. Lang: Rafael How to Fish for WIMPs - m - Space Buchmueller et al. arXiv:1102.4585 5 Kadastik et al. PRL 104 201301 (2010) Roszkowski et al. JHEP07 075 (2007) Baltz&Gondolo PRD 67 063503 (2003) How to Fish for WIMPs • expected recoil spectrum • discrimination techniques • DAMA/LIBRA • CoGeNT • CRESST-II • CDMS-II • EDELWEISS • XENON100 Rafael F. Lang: How to Fish for WIMPs 6 Direct Scattering Theory On One Slide • Rate large detector, long exposure (or ) • Coherent Scattering heavy target material • Maximum Recoil Energy low energy detector • Spectrum shielding, discrimination, multi target Rafael F. Lang: How to Fish for WIMPs 7 Expected WIMP Spectrum • isothermal halo • local density • • coherent scattering m = 1000 GeV • Helm form factor m = 100 GeV m = 10 GeV / ) pb xenon xenon kg d kg on on dE keV ( / dN Recoil Energy / keV Rafael F. Lang: How to Fish for WIMPs 8 Annual Modulation December 60 galactic plane expect modulation of • rate June • spectral shape at the percent level Rafael F. Lang: How to Fish for WIMPs 9 How to Fish for WIMPs • expected recoil spectrum: falling exponential • discrimination techniques • DAMA/LIBRA • CoGeNT • CRESST-II • CDMS-II • EDELWEISS • XENON100 Rafael F. Lang: How to Fish for WIMPs 10 The Power of Discrimination e-/ : electronic recoil n/WIMPs: nuclear recoil electronic recoils • are most common background • scintillate and ionize more (for given energy) → discriminate between the two e.g. measure both energy and some additional parameter (ionization yield, scintillation yield, ratio ionization/ scintillation, pulse decay times, acoustic signal) Rafael F. Lang: How to Fish for WIMPs 11 Particle Detection Channels XENON1T Direction XENON100 WARP ZEPLIN-III ZEPLIN-II WIMP XENON10 LUX DRIFT-II NEWAGE DM-TPC DEAP-I DEAP-3600 miniCLEAN XMASS IGEX Scintillation Ionization CoGeNT DAMA/LIBRA TEXONO XENON10 (S2) KIMS ANAIS XENON100 (S2) DM-ICE Target CDMS CRESST-II SuperCDMS ROSEBUD EDELWEISS Bubble Axion Nucleation Cavities Phonons COUPP PICASSO ADMX CRESST-I SIMPLE Rafael F. Lang: How to Fish for WIMPs 12 Particle Detection Channels XENON1T XENON100 Direction Scintillation Ionization CoGeNT DAMA/LIBRA Target CRESST-II CDMS EDELWEISS Bubble Axion Nucleation Cavities Phonons Rafael F. Lang: How to Fish for WIMPs 13 How to Fish for WIMPs • expected recoil spectrum: falling exponential • discrimination techniques: help increase sig/bck • DAMA/LIBRA • CoGeNT • CRESST-II • CDMS-II • EDELWEISS • XENON100 Rafael F. Lang: How to Fish for WIMPs 14 Gran Sasso Underground Lab Gran Sasso mountain range cable car to ski resort hiking path lab tunnel Assergi highway Rafael F. Lang: How to Fish for WIMPs 15 DAMA/LIBRA Italy/China: 230kg ultra-pure NaI(Tl) scintillators by far largest and longest exposure but no discrimination Rafael F. Lang: How to Fish for WIMPs 16 DAMA/LIBRA Data exposure now exceeds 1 ton year +0.05 keV 0 modulation counts/kg/d/ arXiv:0804.2741 -0.05 Energy / keV observe rate modulation in [2,4]keV: data fromdata arXiv:0804.2741 and arXiv:1002.1028 Rafael F. Lang: How to Fish for WIMPs 17 Muon Flux at Gran Sasso DAMA: May 26 7d ICARUS n LVD : July 15 15d DAMA and LVD μ phase are roughly consistent. • 2/dof ~ 1 arXiv:1110.0857 • delayed phosphorescence? (error bars?) arXiv:1102.0815 • n generation in the passive shielding? arXiv:1006.5255 • pure coincidence? arXiv:0912.0660 Rafael F. Lang: How to Fish for WIMPs 18 DAMA Interpreted as WIMPs DAMA arXiv:0912.4264 a bit low in mass and a bit high cross section, but a priori OK Kopp,Schwetz,Zupan Rafael F. Lang: How to Fish for WIMPs 19 How to Fish for WIMPs • expected recoil spectrum: falling exponential • discrimination techniques: help increase sig/bck • DAMA/LIBRA: claims discovery • CoGeNT • CRESST-II • CDMS-II • EDELWEISS • XENON100 Rafael F. Lang: How to Fish for WIMPs 20 CoGeNT Performance USA 440g P-type point-contact Ge detector conventional coaxial HPGe P-type point- contact HPGe threshold 400eV Collar, Collar, UC Davis and other talks, 2010 Rafael F. Lang: How to Fish for WIMPs 21 CoGeNT Data noise pedestalnoise arXiv:1002.4703 arXiv:1106.0650 ~3 modulation after 15months. Background rejection? expected phase fit Rafael F. Lang: How to Fish for WIMPs 22 CoGeNT Surface Cut arXiv:1002.4703 cutting at constant acceptance! Rafael F. Lang: How to Fish for WIMPs 23 CoGeNT @ TAUP J. Collar, TAUP 2011 lower limit shifts down by many sigma. Still different from zero? Rafael F. Lang: How to Fish for WIMPs 24 CoGeNT Interpreted as WIMPs DAMA CoGeNT , IDM2010 another allowed region at low masses and relatively high cross sections Schwetz Rafael F. Lang: How to Fish for WIMPs 25 How to Fish for WIMPs • expected recoil spectrum: falling exponential • discrimination techniques: help increase sig/bck • DAMA/LIBRA: claims discovery • CoGeNT: quasi-exponential background, modulation • CRESST-II • CDMS-II • EDELWEISS • XENON100 Rafael F. Lang: How to Fish for WIMPs 26 CRESST-II Germany, Italy; at the Gran Sasso lab 8 scintillating 300g CaWO4 calorimeters (phonon/light) thermometer ∆R threshold <20eV light esistance r absorber ∆T temperature clamps crystal phase transition thermometer scintillating h/ =40mm, m=300g reflector Rafael F. Lang: How to Fish for WIMPs 27 CRESST-II Germany, Italy; at the Gran Sasso lab 8 scintillating 300g CaWO4 module ∆R esistance r ∆T temperature thermal shields module h/ =40mm, m=300g holder Rafael F. Lang: How to Fish for WIMPs 28 CRESST Data Example here: channels 5&6 from current data taking keV / ee light yield / keV/ yield light Seidel, IDM2010 energy / keV Rafael F. Lang: How to Fish for WIMPs 29 CRESST Background precise calorimetric measurement of electronic recoils keV / ee . Phys. 32 318 (2010) e.g. find 41Ca K at 3.6keV Astropart light yield / keV/ yield light Seidel, IDM2010 energy / keV Rafael F. Lang: How to Fish for WIMPs 30 CRESST Discrimination where are -events and O/W/Pb recoils? ,e- He( ) O Ca keV / ee W Pb measured quenching factors New J.New Phys. 11 (2010) 105017 light yield / keV/ yield light Seidel, IDM2010 energy / keV Rafael F. Lang: How to Fish for WIMPs 31 CRESST Data Example what are all these events below the electronic recoil band? Target is CaWO4 ! keV / ee and e- band light yield / keV/ yield light band O-band (n) W-band (WIMP) Seidel, IDM2010 energy / keV Rafael F. Lang: How to Fish for WIMPs 32 CRESST Background 210Po → 206Pb (104keV) + (5.4MeV) crystal passive surface X keV / ee Pb Pb Pb light yield / keV/ yield light Pb Seidel, IDM2010 energy / keV scintillator Rafael F. Lang: How to Fish for WIMPs (most surfaces) CRESST Combined Results few events in W band, but 67 events in O band take all 8 detectors together and estimate events from known backgrounds that could leak into signal region: keV neutrons: ~ 8 / ee alphas: ~12 leaking e-/ : ~ 8 210Pb: ~15 sum: ~43 → WIMPs: ~25? light yield / keV/ yield light Seidel, IDM2010 energy / keV arXiv:1109.0702 Rafael F. Lang: How to Fish for WIMPs 34 CRESST Oxygen Events as WIMPs DAMA CoGeNT CRESST yet another region… arXiv:1109.0702 Rafael F. Lang: How to Fish for WIMPs 35 CRESST Limits from Others DAMA CoGeNT CRESST arXiv:1109.2589 arXiv:0911.0929 yet another region… mostly excluded by its own, previous data set Rafael F. Lang: How to Fish for WIMPs 36 How to Fish for WIMPs • expected recoil spectrum: falling exponential • discrimination techniques: help increase sig/bck • DAMA/LIBRA: claims discovery • CoGeNT: quasi-exponential background, modulation • CRESST-II: lots of events • CDMS-II • EDELWEISS • XENON100 Rafael F. Lang: How to Fish for WIMPs 37 CDMS-II USA/Canada/Switzerland located at Soudan 19 Ge and 11 Si “ZIP” detectors with phonon (TES) and ionization signal data-taking finished , IDM2010 final analysis of 2 years data from 14 250g Ge detectors Armengaud next step: SuperCDMS with bigger and interleaved detectors Rafael F. Lang: How to Fish for WIMPs 38 CDMS-II Results calibration data: bulk electronic recoils surface events bulk nuclear recoils arXiv:0912.3592 Rafael F. Lang: How to Fish for WIMPs 39 CDMS-II Results Ge dark matter search data two detectors with signal candidate events combined: bulk electronic recoils surface events bulk nuclear recoils two events observed, consistent with (revised) background expectation of 0.9 0.2 events. In addition, neither event golden arXiv:0912.3592 arXiv:0912.3592 and Saab, IDM2010 Rafael F. Lang: How to Fish for WIMPs 40 CDMS Limit DAMA CoGeNT CRESST CDMS 1619 1619 (2010), arXiv:0912.3592 327 CDMS collaboration does not claim any Dark Matter signal (2 events observed over 0.9 0.2 expected) Science Rafael F. Lang: How to Fish for WIMPs 41 CDMS-II Low Threshold Results dedicated analysis with threshold lowered to 2keV to test CoGeNT (also Ge!) indication at the expense of additional background data from one (of 8) detectors: arXiv:1011.2482 Rafael F.