UW River Falls, May 15-16, 2003 Searching for Dark Matter Through South Pole Ice Kurt Woschnagg University of California - Berkeley
Mar 28, 2015
UW River Falls, May 15-16, 2003
Searching for Dark Matter Through South Pole Ice
Kurt WoschnaggUniversity of California - Berkeley
UW River Falls, May 15-16, 2003
Outline of Talk
• Introduction• What’s the Matter with Matter?• Are WIMP’s What’s Missing?• WIMP Detection and Neutrinos• Detecting Neutrinos with Ice(Cube
& AMANDA)• Summary
UW River Falls, May 15-16, 2003
IntroductionEdwin Hubble 1929: The Universe is expanding!
What’s the fate?
Too much Just right Too little
Big CRUNCH Vast EXPANSE
UW River Falls, May 15-16, 2003
1999: Accelerating Expansion !!
UW River Falls, May 15-16, 2003
UW River Falls, May 15-16, 2003
What’s the Matter with Matter?
• It’s Missing!– Let 0 be the energy density of the
Universe
– Evidence Suggest 0=1• Cosmic Microwave Radiation Background
measurements beginning• High Red-shift Type 1a supernovae long ago• Matter observations recent
UW River Falls, May 15-16, 2003
What’s the Matter with Matter?
Baryonic Matter5%
Dark Matter 35%
Dark Energy60%
Ordinary Matter is less than 0.05 0
UW River Falls, May 15-16, 2003
Are WIMP’s What’s Missing?
• Relics from the past– Weakly Interacting Massive Particles
• Weak interactions → Survival • Appreciable Mass
• Neutralinos to the rescue– Scatter off nuclei of ordinary matter– Become gravitationally trapped in the
Earth – Neutrinos produced from annihilations
UW River Falls, May 15-16, 2003
WIMP annihilation
qqllWWZZ,
Higgs…
Earth
Detector
UW River Falls, May 15-16, 2003
Neutrinos: The Ideal Messengers?
• Neutral– Not affected by magnetic fields
• Weakly interacting– Pass (straight) through intervening
matter– Escape high-density/energy environment
• Abundant– Most prevalent particles
UW River Falls, May 15-16, 2003
Neutrinos have helped us before:
In our solar system:Neutrinos from the Sun prove internal fusion
Just outside our galaxy:Neutrinos from Supernova 1987A explain last gasp of dying stars
Well beyond our galaxy:Neutrinos from massive Black Holes…some dayNeed to look at higher energies → larger detectors!
However…
UW River Falls, May 15-16, 2003
““I have done a terrible I have done a terrible thing, I have invented a thing, I have invented a particle that cannot be particle that cannot be
detected.”detected.”Wolfgang PauliWolfgang Pauli
Only weak interactions → indirect detection
UW River Falls, May 15-16, 2003
How to build a neutrino detector
• Look for the neutrino’s interaction product (e,,)
• Use the earth as a filter
• Needle in haystack: 1 in 1,000,000 is
Earth
Detector
cosmic ray
UW River Falls, May 15-16, 2003
Cherenkov radiation: sonic boom of light
How to detect muons from neutrinos
UW River Falls, May 15-16, 2003
• Need something transparent• Need large volume of it• Can’t pay a lot for it• Need electricity, food, transportation, etc
• Antarctic ice is the purest, most transparent natural medium on earth• South Pole ice cap is two miles thick• South Pole ice is “free”• US has permanent base at South Pole
Build it at the South Pole!
UW River Falls, May 15-16, 2003
AMANDAAntarctic Muon and Neutrino Detector
Array
– 677 light sensors– 200 m diameter, 600m high – Buried under 1400 m of ice
Popular ScienceApril, 2001, p. 70Hunting the Invisible
~4 neutrinos per day
UW River Falls, May 15-16, 2003
UW River Falls, May 15-16, 2003
Holes are drilledwith hot water
2000 m deep60 cm wide3-4 days
UW River Falls, May 15-16, 2003
UW River Falls, May 15-16, 2003
Antarctic geography
South PoleAmundsen-Scott station (US)
McMurdo station
Lake Vostok
New Zealand & US
Greenwich (UK)
UW River Falls, May 15-16, 2003
UW River Falls, May 15-16, 2003
UW River Falls, May 15-16, 2003
UW River Falls, May 15-16, 2003
Amundsen-Scott South Pole station
South PoleDome
Skiway
Summer camp
IceCube
AMANDA
“North”
Dark sector
UW River Falls, May 15-16, 2003
UW River Falls, May 15-16, 2003The
Dome
The new station
UW River Falls, May 15-16, 2003
Summer camp
UW River Falls, May 15-16, 2003
The AMANDA counting house:MAPO (Martin A. Pomerantz Observatory)
UW River Falls, May 15-16, 2003
WIMPs seen so far: 0
• Just started looking• Need more time to catch one, or
• Need bigger detector →
IceCube – 1 km3 of ice
UW River Falls, May 15-16, 2003
IceCubeIceCube1400 m
2400 m
AMANDA
South Pole
Skiway
80 Strings 4800 sensors 1 km3 volume (1Gt) First string to be
deployed in Dec 2004 To be completed in
2010 AMANDA contained
within IceCube~300 neutrinos per day
SurfaceIceTop
UW River Falls, May 15-16, 2003IceTop tank
UW River Falls, May 15-16, 2003
11 US and 10 European institutions and 1 Japanese university11 US and 10 European institutions and 1 Japanese university (most of them are also AMANDA member institutions)(most of them are also AMANDA member institutions)
1. Bartol Research Institute, University of Delaware2. BUGH Wuppertal, Germany3. Universite Libre de Bruxelles, Brussels, Belgium4. CTSPS, Clark-Atlanta University, Atlanta USA5. DESY-Zeuthen, Zeuthen, Germany6. Institute for Advanced Study, Princeton, USA7. Dept. of Technology, Kalmar University, Kalmar, Sweden8. Lawrence Berkeley National Laboratory, Berkeley, USA9. Department of Physics, Southern University and A\&M College, Baton Rouge, LA, USA10. Dept. of Physics, UC Berkeley, USA 11. Institute of Physics, University of Mainz, Mainz, Germany12. Dept. of Physics, University of Maryland, USA13. University of Mons-Hainaut, Mons, Belgium14. Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA15. Dept. of Astronomy, Dept. of Physics, SSEC, PSL, University of Wisconsin, Madison, USA16. Physics Department, University of Wisconsin, River Falls, USA17. Division of High Energy Physics, Uppsala University, Uppsala, Sweden18. Fysikum, Stockholm University, Stockholm, Sweden19. University of Alabama, Tusceloosa, USA20. Vrije Universiteit Brussel, Brussel, Belgium21. Chiba University, Japan22. Imperial College London, UK
The IceCube CollaborationThe IceCube Collaboration
UW River Falls, May 15-16, 2003
Summary
• Only 5% of matter is ordinary matter• WIMPs are missing-matter candidates• Neutrinos can be used to detect WIMPs• Neutrinos are detected indirectly• AMANDA (and soon IceCube) looks for
WIMPs trapped in the center of the Earth and the Sun