New results from an instrument that detects energetic particles in the upper altitudes above Antarctica show an excess of cosmic-ray electrons that may be a signal of dark matter, researchers say. The study, published today by Nature, examines data from a balloon-borne detector called ATIC (Advanced Thin Ionization Calorimeter). The unexpected wealth of electrons in a specific energy range, about 300 to 800 giga-electron-volts, points to a nearby source, the authors write.

One of the possible sources is the annihilation of dark matter, a mysterious type of particle that current theories indicate is many times more prevalent in the universe than the ordinary matter we can see and touch. Some candidates for dark matter, including the so-called Kaluza-Klein particles, would have energies that fit the bill. (The authors speculate that other astronomical objects, such as pulsars or microquasars, could also be responsible.)

The direct detection of dark matter through its production of more mundane particles such as electrons or photons, rather than the inference of its presence through its gravitational pull, would add a new chapter to particle physics. And the characterization of dark matter, the authors write, could even point the way to extra dimensions of space that some theories propose but that we cannot see.

CREDIT: T. Gregory Guzik/Louisiana State University