TOKYO (AP) -- Scientists on the track of the universe's missing antimatter are finding some encouraging clues to one of the great puzzles of physics, they announced at a conference on Monday, July 31.
Two worldwide teams of collaborators -- the California-based BaBar project and the Belle project based in Japan -- are trying to find out more about the differences between matter and antimatter, a topic that gets to the heart of the construction of our world.
"What we're trying to do is understand the most fundamental building blocks of the universe,'' BaBar project spokesman David Hitlin said after he and other researchers announced their findings. "Over time, you develop a true understanding of how the universe is composed, how it developed from the time of the Big Bang.''
Theoretically, nature is symmetrical: Every known subatomic particle, the matter that makes up the world, is paired with an antiparticle of antimatter.
Early in the life of the universe, scientists say, there were equal amounts of matter and antimatter. Today, antimatter is found only in cosmic rays and particle accelerators. The universe is apparently made up of matter only.
Where did all that antimatter go?
An apparent violation of the rule of particle-antiparticle mirror imagery, a theory called "CP violation'' or "charge-parity violation,'' helps explain what we understand now about how our matter-dominated universe came to be.
The BaBar and Belle project teams are examining B mesons -- a subatomic particle that contains the "beauty" quark (one of several varieties of quark) -- for differences in the way they and their antiparticles decay. Differences would be examples of CP violation.
Indications of CP violation in B mesons were found by researchers at the Fermi National Accelerator Laboratory outside Chicago in 1998 and 1999. CP violation has only been conclusively observed in another kind of particle -- K mesons.
A researcher on the 1998 project, Gerry Bauer of the Massachusetts Institute of Technology, said the research by Babar and Belle could lead some very interesting places.
Ultimately, the goal is to find a conflict with the Standard Model of the world's elementary particles and their interactions, he said.
The Standard Model makes a certain prediction about CP violation. If the B meson experiments conclusively find something different, that would reveal a flaw in the Standard Model -- and would make room for research into alternative models such as string theory, which posits that all the particles that make up the world are tiny vibrating loops.
Most everyone in the field thinks the Standard Model is incomplete. If anyone can find a way to show its insufficiency, Bauer said from Fermilab, "Then everyone's very excited.''
People are "desperately trying'' to find deviations because theorists have outpaced the experimental data in particle physics, with lots of interesting, promising ideas such as string theory but no way to assess them yet.
"String theory has the potential to show that all of the wondrous happenings in the universe...are reflections of one grand physical principle, one master equation,'' said string theorist Brian Greene in his recent book, The Elegant Universe.
Bauer called the Belle and BaBar results milestones in a long program that began with the discovery of CP violation in 1964, which won the finders a Nobel Prize.
BaBar is based at the Stanford Linear Accelerator Center in California and Belle is based at KEK, a Japanese national laboratory for high energy accelerator research in Tsukuba City, near Tokyo.
Belle's results are good, but not yet statistically strong enough to make definitive statements, spokesman Fumihiko Takasaki said from the International Conference on High Energy Physics.
"It's a hint of CP violation in B meson decay,'' he said. ``This is a very good start.''
BaBar's news, the first from the new collider, was: "These experiments work well. They work better at an earlier stage than anyone had believed they could,'' Hitlin said.
It is a first step, with more data, more precise measurements and more significant findings expected in a year or so, though no one knows what those findings will be.
The Belle team aims to submit its findings to a scientific journal in October or November. The BaBar team will publish in six months or so.
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