B-Bbar oscillation

The existence of neutral B meson oscillations is a fundamental prediction of the standard model of particle physics. The theory predicts that the neutral B mesons will change form between their matter and antimatter forms before the B decays.

The B-Factories

The observation of the B-Bbar mixing phenomena led physicists to propose the construction of B-factories in the early 1990s. They realized that a precise B-Bbar oscillation measure could pin down the unitarity triangle and perhaps explain the excess of matter over antimatter in the universe. To this end construction began on two B-factories in the late nineties, one at the Stanford Linear Accelerator Center (SLAC) in California and one at KEK in Japan. These B-factories, BaBar and Belle, were set at the Upsilon(4S) resonance which is just above the threshold for decay into two B mesons. After several years they confirmed that the standard model was correct to high precision in this area.

B_s Oscillations

The B_s meson can exist as either a bound state of a anti-strange and bottom quark, or a strange and anti-bottom quark. The oscillations in the neutral B sector are analogous to the phenomena that produces long and short-lived neutral kaons. B_s mixing was observed by the CDF experiment at Fermilab in 2006 .

See also

*B-sub-s meson

References and External Links

* [http://www.slac.stanford.edu/spires/find/hep/www?j=PHLTA,B192,245 Paper describing the discovery of B-meson mixing by the ARGUS Collaboration]
* [http://www-public.slac.stanford.edu/babar/ BaBar Public Homepage]
* [http://belle.kek.jp/ Belle Public Homepage]
* [http://www.fnal.gov/pub/presspass/press_releases/CDF_04-11-06.html Fermilab press release from April 2006]
* [http://www.fnal.gov/pub/presspass/press_releases/CDF_meson.html September 2006 press release regarding 5 sigma discovery]