Comparison of B factories

The B factory is a high-strength accelerator that is designed to study the origins of the flavor and CP violation through accurate measurement of the decay of B mesons. This type of accelerators can be divided into three groups. Those used at DORIS (West Germany) and CESR (U.S.), called symmetric colliders, are intended to cause electrons and positrons having the same energy to collide with each other to produce a BB resonance state. Compared to these, an accelerator designed to produce a BB resonance state by causing electrons and positrons with different energies to collide is called an asymmetric collider. The present study compares the accelerator at CESR, the one at LEP, and the asymmetric collider at KEK. Their luminosity, the number and type of B mesons to be formed, and events to be observed are tabulated. Their comparison is also made with respect to major physical quantities hoped to be determined from B meson experiments, possible methods for them, and their advantages. Such major physical quantities include the probability of the decay from the b quark to the u quark, the mixing of Bs mesons and their anti-particles, and the CP violation. (N.K.)