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Cryogenic Dark Matter Search Harry Nelson UCSB Journal Club March 12, 2004
HNN
CDMS Collaboration
Brown University
Stanford University
M. Attisha, R.J. Gaitskell, J-P. Thompson
Case Western Reserve University D.S. Akerib, M.R. Dragowsky, D.Driscoll, S. Kamat, T.A. Perera, R.W. Schnee, G.Wang
Fermi National Accelerator Laboratory D.A. Bauer, M.B. Crisler, R. Dixon, D. Holmgren, E. Ramberg
Lawrence Berkeley National Laboratory J.H Emes, R.R. Ross, A. Smith
Princeton University T. Shutt
Santa Clara University B.A. Young
3/12/04
UCSB
Cryogenic Dark Matter Search
L. Baudis, P.L. Brink, B. Cabrera, C. Chang, W. Ogburn, T. Saab
University of California, Berkeley M.S. Armel, A. Lu, V. Mandic, P.Meunier, N. Mirabolfathi, W. Rau, B. Sadoulet, D. Seitz, A. Spadafora, K. Sundqvist
University of California, Santa Barbara R. Bunker, D.O. Caldwell, R. Ferril, R. Mahapatra, H. Nelson, J. Sander, C. Savage, S. Yellin
University of Colorado at Denver M. E. Huber
University of Minnesota P. Cushman, L. Duong, A. Reisetter
Cornell Journal Club
2
HNN
UCSB
Plan z
Massive Dark Matter
z
Direct Detection
z
The ZIP Detector
z
Data
z
Future
3/12/04
Cornell Journal Club
3
HNN
Primack Pyramid
UCSB
We are 1 in 10,000 of the energy in Universe… Our form of matter less than dark matter by factor of 5 or so in energy... Who ordered that?
3/12/04
Cornell Journal Club
4
HNN
Leading Thinkers
3/12/04
Cornell Journal Club
UCSB
5
HNN
z
Origin of Dark Matter
During inflation 〉 〉
Axion, superpartner Axino *Zillas →Could
〉
z
UCSB
have only gravitational interactions!
Few constraints…
During thermal equilibration phase of Big Bang… 〉 〉
3/12/04
m > few keV (currently observed large scale structure) m > 10 or so GeV (nothing new at accelerators)
Cornell Journal Club
6
HNN
UCSB
Candidates
3/12/04
Cornell Journal Club
7
HNN
UCSB
Coincidence or Clue… `WIMP’ ’
3/12/04
Cornell Journal Club
8
HNN
WIMP/nucleon σ≈10-42 cm
UCSB
Exper. CDMS DAMA Theory SUSY: various constraints including Big Bang
3/12/04
Cornell Journal Club
9
HNN
Galactic Dark Matter
UCSB
R is the distance from center v
v is the speed (tangential)
R
3/12/04
Cornell Journal Club
10
HNN
UCSB
The Dark Ball Bulge
3/12/04
Disk
Cornell Journal Club
Dark Matter `Halo’ (aka Aura)
11
HNN
UCSB
What about our home galaxy (Milky Way)? χ
χ
χ χ
χ
χ χ
χ
χ
χχ
χ
χ
χ
χχ
χ
χ
χ
χ
χ
χ
χ
χ χ
χ
Honma and Sofue, 1996
v 220 km/s Without the Dark Halo (Binney & Tremaine)
∆:v0=180 km/s ⊕
3/12/04
Cornell Journal Club
R 12
HNN
From Galactic Astrophysics… z
Local energy density, speed of DM MeV ú 0 ø 300 3 cm
0? (200-2000)
z
UCSB
DM at rest:
3/12/04
km v 0 ø 220 (ì 0 ø 7 â 10 à4) s (ì 20 ø 12 â 10 à6) (170-270)
〈vDM〉=0 (sun plowing through at v0 ≈ 220 km/s) 2 〉1/2 ≈ 300 km/s… useful to approximate ≈ 0 〈vDM
Cornell Journal Club
13
HNN
Direct Detection: Signal and Main Background
Signal
Nucleus Recoils
Background Electron Recoils
Er
v/c ≈ 7×10-4 dense energy deposition ionization efficiency low distinct ionization energy scale
0 χ (calibrate: neutron) 3/12/04
UCSB
γ
Er v/c ≈ 0.3
Sparse Energy Deposition
Differences the Basis of Particle ID
Cornell Journal Club
14
HNN
Rate of Main Background
UCSB
≡ DRU • Shield (shield radioactive too!)… 1 ev/(kg d keV) typical • Reduce the background… HDMS , IGEX , Genius • Exploit astron. properties (year cycle, directionality) DAMA, DRIFT • Devise detectors that can distinguish nuclear recoil from electron recoil… Edelweiss, CDMS, Xenon.. 3/12/04
Cornell Journal Club
15
HNN
UCSB
Nuclear Recoil – Cross Section
∝A4
`scalar’ or SI (Spin Independent) 3/12/04
Cornell Journal Club
16
HNN
Nuclear Recoil – Diffraction
UCSB
Iodine (A=127) DAMA 0 110 220 330 keV ER 3/12/04
Cornell Journal Club
17
HNN
UCSB
Nuclear Recoils from Massive Dark Matter z
Deposit 10’s of keV; high target A favored
z
Target A
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