By Peter Weiss
Physicists have added another piece to the puzzle of why so little antimatter exists in today’s universe.
In theory, the explosive birth of the universe produced equal amounts of matter and antimatter. Those incompatible substances didn’t completely annihilate one another. Enough matter survived to form galaxies and other features of the universe. However, scientists looking for naturally occurring antimatter have found only a smidgeon of it, for instance, in cosmic rays.
Researchers explain matter’s dominance as a consequence of differences in the way a fundamental force of nature, called the weak force, affects subatomic particles and their antiparticles. Since the 1960s, experimenters have found such differences, or charge-parity (CP) violations, among particles known as kaons (SN: 3/6/99, p. 148). In 2001, researchers in California and Japan uncovered a type of CP violation among B mesons (SN: 3/3/01, p. 143: Available to subscribers at Physicists get B in antimatter studies).