B-factory interaction region design

High luminosity B-factories are generally high current (1-3 A) e/sup +/e/sup -/ storage ring accelerators that operate at a center-of-mass energy equal to the mass of the Upsilon(4S) resonance (10.58 GeV). The high beam currents are achieved by storing a large number of bunches (several hundred to several thousand) into each beam. Two designs, the ones located at SLAC and KEK, also have asymmetric beam energies. This imparts a boost to the nearly stationary B mesons formed from the decay of the 4S resonance and allows precision vertex tracking detectors to look for a difference between the decay profiles of the matter and anti-matter B mesons, thereby observing a violation of CP.