"You could argue that it was not an unexpected particle, but the implications for its discovery and the amount we found agrees with what we were expecting," Geurts said. "We can now see an extension of the periodic system of elements into regions of antimatter and strange matter."
The new observation tops the previous find of an antihydrogen nucleus containing three particles, including an anti-strange quark, by the same team a year ago. The new record will probably stand for a long time, Geurts said.
He suggested even heavier antimatter particles might be found -- but probably not on this planet. A statement from Brookhaven noted that antilithium-6, a heavier antimatter nucleus that does not undergo radioactive decay, is predicted to be a million times more rare, and its discovery is well outside the reach of current technology.
More basic discoveries could be made in distant galaxies where antimatter from the Big Bang may still be detected. The Alpha Magnetic Spectrometer (AMS) that will be mounted on the International Space Station will measure cosmic rays for evidence of dark matter and antimatter. The space shuttle Endeavor will carry the instrument to the ISS if it launches April 29 as planned.
AMS will also look for antihelium-4 that, if found, could be evidence of the existence of larger regions of the universe made entirely of antimatter. The STAR measurement will help scientists understand the conditions in the very early universe that would allow such antimatter galaxies to form.
The discovery of the anti-alpha comes on the centennial of Ernest Rutherford's first modeling of the atom using alpha particles.
|Contact: David Ruth|