Tevatron particles shed light on antimatter mystery
From New Scientist, July 5, 2011
Why the universe is filled with matter rather than antimatter is one of the great mysteries in physics. Now we are a step closer to understanding it, thanks to an experiment which creates more matter than antimatter, just like the early universe did.
Our best understanding of the building blocks of matter and the forces that glue them together is called the standard model of particle physics. But this does a poor job of explaining why matter triumphed over antimatter in the moments after the big bang.
The standard model has it that matter and antimatter were created in equal amounts in the early universe. But if that was the case they should have annihilated in a blaze of radiation, leaving nothing from which to make the stars and galaxies. Clearly that didn't happen.
A quirk in the laws of physics, known as CP violation, favours matter and leaves the universe lopsided. The standard model allows for a small amount of CP violation but not nearly enough to explain how matter came to dominate. "It fails by a factor of 10 billion," says Ulrich Nierste, a physicist at the Karlsruhe Institute of Technology in Germany.
Now researchers at DZero, an experiment at the Tevatron particle accelerator at Fermilab in Batavia, Illinois, have found the largest source of CP violation yet discovered. It comes courtesy of particles known as Bs mesons.