By sifting through the decays of more than 200 million pairs of B and anti-B mesons, BaBar experimenters have discovered striking matter-antimatter asymmetry. “We found 910 examples of the B meson decaying to a kaon and a pion, but only 696 examples for the anti-B mesons,” Giorgi explained.
While BaBar and other experiments have observed matter-antimatter asymmetries before, this is the first instance in B decays of a difference obtained by simply counting up the number of matter and antimatter decays, a phenomenon known as direct charge parity (CP) violation.
“We have observed a clear, strong signal for asymmetrical behavior of matter and antimatter resulting from the direct CP violation mechanism,” said James Olsen of Princeton University, one of the leaders of the analysis.
The new observation of a 13 percent preference for the B meson over the anti-B meson dwarfs a similar effect observed in kaons at only a tiny rate of 4 parts in a million. “The effect we have measured with B mesons is roughly 100,000 times stronger than for kaons,” Olsen said. “The pattern of different types of matter-antimatter asymmetries is starting to come together into a coherent picture.”
“This is another great scientific achievement for the B-factory at SLAC,” said Raymond L. Orbach, Director of the Department of Energy’s Office of Science. “The new result from BaBar, and related measurements at other accelerators around the world, continue to improve our understanding of CP violation and ultimately may tell us why the visible universe is only matter.”
“The new measurement is very much a result of the outstanding performance of SLAC’s PEP-II accelerator and the efficiency of the BABAR detector,” Giorgi said. “The accelerator is now operating at 3 times its design performance and BaBar is able to record about 98 percent of collisions.”
“This is an exciting and beautiful result–it probes a key mechanism underlying the structure and behavior of matter,” said SLAC Director Jonathan Dorfan. “The observation of the direct CP violation effect in B decays is a significant step forward in assembling the pieces of the puzzle of matter versus antimatter.”
What are we saying here? That anti-B mesons decay less frequently than B mesons into kaons and pions? If so, do they then decay into something else, or not at all? Or are we saying that the anti-B mesons take longer then the B mesons to decay into kaons and pions (doing so ouside of the detector’s limits)?
I take it that any of the above is going to require some (further) revision of the Standard Model.
Also, is there a chain if reasoning between this observation and the dearth of observed anti-matter in the universe?