In particle physics, a B-factory, or sometimes a beauty factory,[1] is a collider-based scientific machine designed to produce a large number (of the order of 109) of B mesons and analyze their properties. Tauons and D mesons are also copiously produced at B-factories, which allows precise studies of their properties.

Two B-factories were designed and built in the 1990s. They are both based on electron-positron colliders with the centre of mass energy tuned to the ϒ(4S) resonance peak, which is just above the threshold for decay into two B mesons (both experiments took smaller data samples at different centre of mass energies). The Belle experiment at the KEKB collider in Tsukuba, Japan, and the BaBar experiment at the PEP-II collider at SLAC laboratory in California, USA, completed data collection in 2010 and 2008, respectively.[2]

The B-factories yielded a rich harvest of results, including the first observation of CP violation outside of the kaon system, measurements of the CKM parameters |Vub| and |Vcb|, and measurements of purely leptonic B meson decays.

Proposals for next-generation B-factories include the canceled SuperB designed to be built in Frascati near Rome in Italy, and Belle II in Japan.


  • See also 1
  • References 2
  • Sources 3
  • External links 4

See also


  1. ^
  2. ^ http://www-conf.slac.stanford.edu/babardandd/Documents/DND_Safety_MARrevisionFO2009v4.pdf


  • BaBar homepage
  • Belle homepage
  • SuperB homepage

External links

  • B Factories in 60 seconds from symmetry magazine