May 14, 2001
Scientists have announced the final result of one of nature's best-kept secrets. It is called direct Charge Parity (CP) violation and the subtle effect explains nature's preference for matter over antimatter.
It explains why we are here at all. When the Universe was born there should have been equal amounts of matter and its counter-part, antimatter.
But shortly after the Big Bang all the matter in the Universe should have disappeared as matter and antimatter collided, destroying each other.
But it seems that there is a tiny difference between matter and antimatter that left a bit of matter remaining, out of which galaxies, stars, and you and I formed.
To find the effect, scientists looked at the behaviour of a particular sub-atomic particle, called a neutral K meson, created for a fleeting moment in a giant atom smasher.
Following ten years of detector development, data collection and analysis, the new result is based on the observation of 20 million of CP-violating neutral K meson decays.
The tiny difference in the decay rates of neutral K mesons and their antiparticles has been determined with a precision of one part in a million.
Scientists say that the study of direct CP violation is an example of the rigour involved in the establishment of scientific facts. BBC News: MORE...
Why does CP violation matter to the universe?
Charge, Parity, and Time Reversal (CPT) Symmetry