Harry Nelson UCSB Orsay October 24, 2005 The Latest from CDMS-II on WIMPs Second Results from Soudan! astro-ph/0509259 astro-ph/0509269 available September.

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Presentation transcript:

Harry Nelson UCSB Orsay October 24, 2005 The Latest from CDMS-II on WIMPs Second Results from Soudan! astro-ph/ astro-ph/ available September 12&13, 2005

CDMSHNN 10/24/05 Orsay Seminar 2 CDMS Collaboration Stanford University P.L. Brink, B. Cabrera, J.P. Castle, C.L. Chang, J. CooleyM. Kurylowicz, L. Novak, R. W. Ogburn, M. Pyle, T. Saab, A. Tomada University of California, Berkeley J. Alvaro-Dean, M.S. Armel, M. Daal, J. Fillipini, A. Lu, V. Mandic, P.Meunier, N. Mirabolfathi, M.C.Perillo Isaac, W. Rau, B. Sadoulet, D.N.Seitz, B. Serfass, G. Smith, A. Spadafora, K. Sundqvist University of California, Santa Barbara R. Bunker, S. Burke, D.O. Caldwell, D. Callahan, R.Ferril, D. Hale, S. Kyre, R. Mahapatra, J.May, H. Nelson, R. Nelson, J. Sander, C.Savage, S.Yellin University of Florida L. Baudis, S. Leclerq University of Minnesota J. Beaty, P. Cushman, L. Duong, A. Reisetter Brown University M.J. Attisha, R.J. Gaitskell, J-P. F. Thompson Case Western Reserve University D.S. Akerib, P. Brusov, C. Bailey, M.R. Dragowsky, D.D.Driscoll, S.Kamat, A.G. Manalaysay, T.A. Perera, R.W.Schnee, G.Wang University of Colorado at Denver M. E. Huber Fermi National Accelerator Laboratory D.A. Bauer, R. Choate, M.B. Crisler, R. Dixon, M. Haldeman, D. Holmgren, B. Johnson, W.Johnson, M. Kozlovsky, D. Kubik, L. Kula, B. Lambin, B. Merkel, S. Morrison, S. Orr, E.Ramberg, R.L. Schmitt, J. Williams, J. Yoo Lawrence Berkeley National Laboratory J.H Emes, R. McDonald, R.R. Ross, A. Smith Santa Clara University B.A. Young Cryogenic Dark Matter Search

CDMSHNN 10/24/05 Orsay Seminar 3 Plan Massive Dark Matter Direct Detection CDMS Future

CDMSHNN 10/24/05 Orsay Seminar 4 `We Declare a New Order’ (Joel Primack) Metals (us)  0.01% Visible Baryons  0.5% Dark Baryons  5% Cold Dark Matter (WIMPs?)  25% Cosmological Constant   70%

CDMSHNN 10/24/05 Orsay Seminar 5 Candidates

CDMSHNN 10/24/05 Orsay Seminar 6 Coincidence or Clue… `WIMP’ ’

CDMSHNN 10/24/05 Orsay Seminar 7 00 Neutralino glue H 0,A 0 quarks c,b,t Same for n, p Enhancement from coherence  (# nucleons) 2 `spin independent’

CDMSHNN 10/24/05 Orsay Seminar 8 Experiment CDMS (shallow) DAMA (old!) Theory SUSY, various constraints including Big Bang Gaitskell/Mandic Our Hunting Ground (old, but simple) Weakly Interacting Massive Particle

CDMSHNN 10/24/05 Orsay Seminar cm 2 Large tan , light A 0 models (soon to be probed at Tevatron, and CDMS) Inteference Minimal Supersymmetric Standard Model Scan

CDMSHNN 10/24/05 Orsay Seminar 10 Constrained SUSY Standard Model Scan cm 2 Ellis, Olive, et al. 2005

CDMSHNN 10/24/05 Orsay Seminar 11 Galactic Dark Matter R v v is the speed (tangential) R is the distance from center

CDMSHNN 10/24/05 Orsay Seminar 12 Our home galaxy (Milky Way)?                           Uncertainty: `standard’ ~ 1/3 GeV/cm 3, 220 km/s Gaussian velocity distrib. mainly for comparison Honma & Kan-ya, 1998 

CDMSHNN 10/24/05 Orsay Seminar 13 v/c =   0.7  Modern Chadwick Experiment 00 Massive: M  c 2  100 GeV `Weak Scale’ Germanium, A  73, mc 2  68 GeV; Silicon: A  28, mc 2  26 GeV (better for small M  c 2 ) v/c =   0.7  E R  ½ m Ge(Si) c 2  2  ½ 68 (26) GeV  ½   20 (7) keV  x-ray energy ! Easy! “Direct Detection”

CDMSHNN 10/24/05 Orsay Seminar 14 Catalog of Recoil Experiments Rick Gaitskell

CDMSHNN 10/24/05 Orsay Seminar 15 00 Nucleus Recoils Signal Shape ErEr Silicon, Sulphur Germanium Iodine, Xenon A2A2 M WIMP =100 GeV   cm 2 /nucleon Slope: Gaussian of WIMPs in Galaxy Diffraction

CDMSHNN 10/24/05 Orsay Seminar 16  0 (calibrate: neutron) v/c  7  Nucleus Recoils dense energy deposition efficiency low distinct energy scale Direct Detection: Signal and Main Background Signal ErEr  v/c  0.3 Electron Recoils Background Sparse Energy Deposition ErEr Differences the Basis of Particle ID

CDMSHNN 10/24/05 Orsay Seminar 17 H phonons ionization Q L scintillation CDMS, EDELWEISS CRESST II, ROSEBUD ZEPLIN II, III, MAX, XMAS, XENON NAIAD, ZEPLIN I, DAMA IGEX, DRIFTI, II CRESST I, PICASSO, COUPP Tim Sumner

CDMSHNN 10/24/05 Orsay Seminar 18 Nuclear recoil bad at making ionization Germanium 00 Holes e-e-  more ionization! Both deposit, say, 20 keV Sound !

CDMSHNN 10/24/05 Orsay Seminar 19 Our Detectors `Phonon sensor (4)’ (TES) Ionization Electrodes (2) x-y-z imaging: from sharing, timing Z-coordinate, Ionization, Phonons ZIP Operate at Kelvin

CDMSHNN 10/24/05 Orsay Seminar 20 The Phonon Sensor Al quasiparticle trap Al Collector W Transition-Edge Sensor (TES) Ge or Si quasiparticle diffusion phonons Cooper Pair superconducting normal T (mK) T c ~ 80mK R TES (  ) ~ 10mK R. Schnee

CDMSHNN 10/24/05 Orsay Seminar 21 Pulses Charge (2) Phonon (4) Time (  s) KeV  1 mm/  s

CDMSHNN 10/24/05 Orsay Seminar 22 Separation of the types of recoils Sound Neutrons cause nuclear recoils too! Another background…

CDMSHNN 10/24/05 Orsay Seminar 23 Deep Facility Soudan Mine Hosts: State of Minn., U Minn., Fermilab 690 meters underground 2090 meters water equivalent

CDMSHNN 10/24/05 Orsay Seminar 24 Background Neutrons from Cosmic Ray Muons Limited our earlier results…moved to a deep mine

CDMSHNN 10/24/05 Orsay Seminar 25 Down deep in the Soudan mine HVAC Mechanical RF-shielded Clean room Shield Fridge Front-end Electronics Mezzanine Detector Prep DAQ/Electronics Clean Benches Icebox Pumps, Cryogenics Soudan II MINOS connecting tunnel

CDMSHNN 10/24/05 Orsay Seminar 26 Outside In plastic scintillators outer polyethylene lead ancient lead inner polyethylene

CDMSHNN 10/24/05 Orsay Seminar 27 A Cold Heart 10 cm Two `towers’ Results from first… 6 detectors… ZIP 1 (Ge) ZIP 2 (Ge) ZIP 3 (Ge) ZIP 4 (Si) ZIP 5 (Ge) ZIP 6 (Si) 4 K 0.6 K 0.06 K 0.04 K SQUID cards FET cards 14 C Tower 1: 4 Germanium (0.25 kg each), 2 Silicon (0.1 kg each) poorer resolution

CDMSHNN 10/24/05 Orsay Seminar 28 Detectors Veto Scintillator Polyethylen e Lead Cable s Cry o Radioactiv e Source

CDMSHNN 10/24/05 Orsay Seminar 29  Calibration ( 133 Barium) (e  recoils) Ionization Phonons Energy, KeV L. Baudis

CDMSHNN 10/24/05 Orsay Seminar 30 Better Source, Calibration ( 133 Ba) Ionization Phonons 275 keV ,  =2.5 keV 384  =8 keV

CDMSHNN 10/24/05 Orsay Seminar 31 n Calib. ( 252 Californium) (nuclear recoils) Reconstructed recoil energy, KeV S. Kamat

CDMSHNN 10/24/05 Orsay Seminar 32 First Year of Running CDMS II at Soudan Oct Jan “Tower 1”  53 livedays, 1 kg Ge, 0.2 kg Si Calibration runs Nearly 85% livetime for last six weeks Tower 1 Mar.-Aug “The Two Towers”  74 livedays 1.5 kg of Ge, 0.6 kg of Si  More Barium Calibration extra calibration runs Towers 1 & 2 Livetime (days) Date

CDMSHNN 10/24/05 Orsay Seminar 33 Mask WIMP Search Data oversized nuclear recoil band + Single, Qinner, veto-anticoinc Define cuts on calibration data (E_threshold) Test on Barium and multiple detector events e.g. Decide the trade-off between neutron efficiency and surface beta rejection and estimate leakages Freeze cuts and calculate nuclear recoil band acceptance Unblind Apply cuts to the unmasked WIMP search data Calculate Expected Backgrounds Compare with previous blind tests to estimate systematic uncertainties CDMS Blind Analysis Technique

CDMSHNN 10/24/05 Orsay Seminar 34 ZIP 1 (Ge) ZIP 2 (Ge) ZIP 3 (Ge) ZIP 4 (Si) ZIP 5 (Ge) ZIP 6 (Si) 4 K 0.6 K 0.06 K 0.04 K SQUID cards FET cards 14 C Reject Multiple Interactions 00 WIMPs don’t scatter twice n,  Backgrounds often do Surface electrons

CDMSHNN 10/24/05 Orsay Seminar 35 The Two Tower Data 15 sig. region Z2/Z3/Z5/Z9/Z11 Ionization Yield Recoil Energy (keV) A. Reisetter Surface Electrons Two Tower Run: much focus on rejection of surface events

CDMSHNN 10/24/05 Orsay Seminar Pb peak in adjacent detectors Sometimes a signal in only 1 detector... `single’ Dominantly (2/3) 210 Pb on detector surfaces Balance unknown…

CDMSHNN 10/24/05 Orsay Seminar 37 External e  : surface events, ionization missed Germanium Electrode Implants E  External e   decay contamination, escaping compton recoils z `ZIP’ : `reconstruct’ z with start time, risetime… pulseheight share Ionization not collected

CDMSHNN 10/24/05 Orsay Seminar 38 C. Chang

CDMSHNN 10/24/05 Orsay Seminar 39 00 Primary Phonons `High Energy,’ `Rayleigh Scatter’ so they diffuse + energy downshift Lower Energy Phonons Have Longer Pathlength, Diffuse More Promptly Eventually energy low, pathlength long, `phonons go ballistic’ Phonon Sensors External e   decay contamination, escaping compton recoils Sensor Induces Phonon Energy Downshift Distinct Sensor Sharing

CDMSHNN 10/24/05 Orsay Seminar 40 Pulse Timing (phonon start time) 10-40% G. Wang Timing quantities used to suppress external electrons Ionization Pulse gives start time

CDMSHNN 10/24/05 Orsay Seminar Ionization Yield Recoil Energy (keV) Z2/Z3/Z5/Z9/Z11 23x our WIMP-search background Barium, Neutron Calibration Samples Barium (  ) 252 Cf (n) Enabled by vastly improved DAQ!

CDMSHNN 10/24/05 Orsay Seminar 42 Mean has most of the info… Nuclea r Recoil s Surfac e Events

CDMSHNN 10/24/05 Orsay Seminar 43 Recoil Energy (keV) Ge cut efficiency Used for Ge (cut determined blind) Surfac e Events Nuclea r Recoil s

CDMSHNN 10/24/05 Orsay Seminar 44 Third Variable... make a  2 Surfac e Events Nuclea r Recoil s

CDMSHNN 10/24/05 Orsay Seminar 45 Surfac e Events Nuclea r Recoil s R. Mahapatra J. Sander Used for Si (cut determined blind)

CDMSHNN 10/24/05 Orsay Seminar 46 Before/After Timing Cut 15 sig. region Z2/Z3/Z5/Z9/Z11 Ionization Yield Recoil Energy (keV) A. Reisetter Surface Electrons 1 candidate (barely) 1 near-miss 0.37  0.20 (sys.)  0.15 (stat.) misid’ed electron recoils from sidebands and pre-cut signal region 0.13  0.05(stat) from barium calibration Can cut harder to suppress electron leakage ~0.05 recoils from neutrons

CDMSHNN 10/24/05 Orsay Seminar 47 Small Circles: prior to surface rejection Colored: passing surface rejection Star: one candidate Expected Background (7-100 keV recoil energy) Beta 0.5±0.2±0.2 for Ge and 1.2±0.6±0.2 for Si Neutron 0.06 for Ge and 0.05 for Si

CDMSHNN 10/24/05 Orsay Seminar keV: not included before opening the box for Ge (but was included before opening for Si) Only included for combined Ge limit.

CDMSHNN 10/24/05 Orsay Seminar 49 New Limits (Spin Independent) Silicon: low mass 90% CL About twice more sensitive than 1-tower

CDMSHNN 10/24/05 Orsay Seminar 50 00 Neutralino Z0Z0 Axial vector interaction gives spin-dependent scattering… neutron or proton

CDMSHNN 10/24/05 Orsay Seminar 51 New Limits (Spin Dependent) 8% 73 Ge 5% 29 Si  unpaired neutron Ge (2 nuclear models) Si Super-K Solar Zeplin-I Picasso DAMA CRESST-I NAIAD Majorana neutron proton

CDMSHNN 10/24/05 Orsay Seminar keV x-ray, L- shell Capture 71 Ge SUF Run 21 Germanium – Low Threshold, Shallow Ge Si R. Bunker

CDMSHNN 10/24/05 Orsay Seminar 53 Improvements  Cryogenics, backgrounds, DAQ  Currently commissioning 30 detectors in 5 towers of 6  4.75 kg of Ge, 1.1 kg of Si to run through 2007  Improve sensitivity x10 The Near Future Installed 3 additional towers in November CDMS- Soudan CDMS -projected Edelweiss ZEPLIN-1 Better Radon Suppression

CDMSHNN 10/24/05 Orsay Seminar 54 H. Nelson Background Subtracted Expected exposure for 1 year running 5x improvement via improved discrimination 2.5x improvement via subtraction ignoring systematics Expectations based on SUF backgrounds 1-tower run Combined runs X4 better SUF

CDMSHNN 10/24/05 Orsay Seminar 55 Sensitivity Expectations

CDMSHNN 10/24/05 Orsay Seminar 56 Elements leading to increased sensitivity Thicker Detectors  Less surface/volume, factor of 2.5 Better Analysis Rejection  Better Monte Carlo, reconstruction, factor of 4 Cleaner Detectors  210 Pb … Radon Daughter, factor of 10 Move to SNOLAB to suppress neutrons

CDMSHNN 10/24/05 Orsay Seminar 57 SuperCDMS Roadmap

CDMSHNN 10/24/05 Orsay Seminar 58 Projected Sensitivies

CDMSHNN 10/24/05 Orsay Seminar 59 CDMS Collaboration(March 2002)

CDMSHNN 10/24/05 Orsay Seminar 60 DAMA – 100 kg of NaI Iodine, A=127 E obs (KeV ee )  0.09 E recoil (KeV) Sodium, A=23 E obs (KeV ee )  0.25 E recoil (KeV) E recoil  Light NaI PMT Copper Lead Poly

CDMSHNN 10/24/05 Orsay Seminar 61 through 2000 … 4  DAMA Background and Signal through 2003 … 6.3  Bernabei et al., astro-ph/ Energy Spectrum Bkgd  1 cpd/kg/keV 2-6 KeV 8-24 KeV Na(23) KeV I(127)   cpd/kg/keV

CDMSHNN 10/24/05 Orsay Seminar 62 Rate of Main Background Rate about 10 3 / (kg-day) !!! Shield… but that radioactive too Strategies: DAMA… huge target mass, look for astrophysical modulation CDMS, Xenon… `small’ target mass, distinguish electron from nucl. recoil

CDMSHNN 10/24/05 Orsay Seminar 63 Timing rejects surface/external e  ee Nuclear Recoils External e  Phonon Delay ( µ s)

CDMSHNN 10/24/05 Orsay Seminar 64 CDMS Technique: Phonons v. Ionization Shutt et al., 1992 Nuclear recoils (induced by a neutron source) Electron recoils (induced by a  source) Slope really 1! Ionization Phonons =1 (bkgd)  1/3 (sig) E gap = 3/4 eV w = 3 eV (Ge)