BaBar is investigating the mystery of why there is more matter than antimatter in the Universe. They should have been produced in equal amounts in the Big Bang, so where has all the antimatter gone?
In the 1960s, physicists discovered a slight asymmetry between matter and antimatter. They found that a particle called the neutral kaon () behaved differently from its antiparticle (the ). However, the difference is not enough to account for the massive dominance of matter over antimatter in the Universe today.
BaBar is looking for a similar asymmetry in particles called B mesons (the , and its antiparticle, the ). Theory predicts that the asymmetry will be more pronounced than in the kaons. However, the effect is so small that millions of these particles will have to be observed in order for any differences to be found. They are being produced in the so-called B-Factory.