The collaboration, called CDMS (Cryogenic Dark Matter Search), uses an entirely new type of detector technology that employs crystals kept at cryogenic temperatures to detect potential dark matter particles.

This powerful technology derives its advantage from being able to distinguish background "events" that result from many of the known particles interacting in the crystals from those that are likely to be dark matter interactions. This discrimination allows an unambiguous identification of events in the crystals caused by any new form of matter.

The results of the search were reported Feb. 25, at the Fourth International Symposium on Sources and Detection of Dark Matter in the universe in Marina del Rey, Calif.

Within the currently favored theoretical models these results appear incompatible with the evidence for dark matter reported by the DAMA collaboration last week.

The DAMA (DArk MAtter experiment) is based in Rome and Beijing. The two searches use very different techniques for detecting dark matter particles.

The CDMS collaboration includes groups from UC-Berkeley, Stanford, UC-Santa Barbara, Lawrence Berkeley National Laboratory, Fermi National Accelerator Laboratory (Fermilab), Case Western Reserve University, Santa Clara University, the National Institute of Standards and Technology (Boulder), the University of Colorado at Denver and Princeton.

Their findings have been submitted to Physical Review Letters. The research is supported jointly by the Department of Energy and by the National Science Foundation in a collaboration coordinated by the Center for Particle Astrophysics.

For more than a decade, a number of experiments around the world have searched for dark matter in the form of weakly interacting massive particles (WIMPs).

Theoretically, a million WIMPs would pass through an area the size of a thumbnail each second, but only about one per day would interact (be deflected) in a one-kilogram germanium detector and produce an event that can be measured from the small amount of recoil energy imparted to a single nucleus.

Detectors capable of recording one such event per day per kilogram, or less, are sufficiently sensitive to search for a particular type of WIMP suggested by supersymmetry - by far the most popular extension of the Standard Model of particle physics theory.

Most supersymmetric models predict the existence of such particles, which are called neutralinos. The neutralinos interaction rates are at or below this level.

The discovery of WIMPs would confirm 70 years of combined astrophysics and particle physics research that suggests most of the matter of the universe is dark and is not made of ordinary atoms. The existence of WIMPs is predicted from very general considerations about the big bang and the early universe.

If this intriguing hypothesis turns out to be correct - many have called it the ultimate Copernican revolution - we are not at our solar system's center, not at our galaxy's center, not in a particularly distinguished galaxy, and not even made of the most dominant form of matter in our universe.

Last week, the DAMA collaboration reported on more than three years of data collected with a 100-kilogram sodium iodide detector operated deep underground in the Gran Sasso National Laboratory in Italy.

Their detector produces a flash of light each time there is a particle interaction within its volume. In a statistical analysis of tens of thousands of events, they claim to see a modulation in the event rate with the same period as Earth's solar year, with a maximum in June and a minimum in December.

Detecting Dark Matter - Part Two