BaBar Experiment Studies Antimatter
See story on page 4. In the BaBar experiment at SLAC, separate beams of electrons and positrons are propelled through the two-mile accelerator (shown diagonally) and then circulated in opposite directions around two large rings of magnets. The particles collide in the BaBar detector (at bottom), creating B mesons and anti-B mesons. Differences in these particles' rates of decay may help scientists understand why the "big bang" resulted in more matter than antimatter in the universe today.
Illustration provided courtesy of the Stanford Linear Accelerator Center and U.S. Department of Energy.