Recent Science Results
- Dark Matter Search Results from the CDMS II Experiment (Feb. 2010)
- Results From the Final Exposure of the CDMS II Experiment (Dec. 2009)
- Analysis of the low-energy electron-recoil spectrum of the CDMS experiment (Jul. 2009)
- Search For Axions with the CDMS Experiment (Mar. 2009)
- A Search for WIMPs with the First 5-Tower Data from CDMS (Mar. 2008)
- All Publications
- CDMS Theses
Collaborators
CDMS At Texas A&M
There is a great deal of evidence exists indicating that about 80% of the matter in the universe is dark which is to say it doesn't interact with light and can not be observed with telescopes. While we do know know what the dark matter is made of, we do know that the vast majority of dark matter mush be composed of a type of matter never before observed. One of the most popular candidates for the dark matter are Weakly Interacting Massive Particles (WIMPs).
Dark matter is the dominant form of matter holding together galaxies including our own galaxy. In fact, a two liter bottle would typically hold one WIMP. Because the WIMPs near the sun feel the same gravitational pull that we do, they move with a similar speed as the sun or about 220 kilometers per second or about 500 miles per hour. Because WIMPs do not interact via the strong or electro-magnetic forces, they interact only rarely.
The CDMS II experiment attempts to observe WIMP interactions through their elastic scattering of target nuclei in detectors with very low detection thresholds. The detectors are made of germanium (Ge) or silicon (Si) crystals and are sensitive to events with recoil energies of a few tens of keV. Expected event rates are less than 1 event/kg-day.
Electromagnetic backgrounds, such as natural radioactivity, produce a far higher rate of events with similar energy. CDMS handles these backgrounds by using lead to shield the detectors and by developing detectors that are able to discriminate between electromagnetic events (background) and nuclear recoils (possible WIMP events).
Cosmic ray interactions can induce nuclear recoils. Therefore, the CDMS II experiment operates deep underground to use the earth above to protect them from cosmic rays. The CDMS II experiment operating in the Soudan Underground Laboratory 2341ft underground (200 meters water equivalent) reducing the relevant (muon) flux by a factor of 50,000.
CDMS has one of the most sensitive exclusion limit on the WIMP neutralino dark matter cross section with ordinary matter, at 4x10-44 cm2. The next upgrade of CDMS, named SuperCDMS, to be operated in a deeper underground site, has a target sensitivity that will be 100 times better, to be achieved within the next 4 years. CDMS and SuperCDMS will continue to maintain their world leading sensitivity for the next few years to come, either discovering the WIMP dark matter or excluding a large part of the SUSY parameter space, thus fundamentally changing our ideas of the expected SUSY signature.
Last updated Sept. 7 2011.