B factory

A B factory is a particle physics apparatus designed to create B mesons, which are mesons that contain one bottom antiquark and one quark of a different flavor. In a B factory, electrons and positrons from an accelerator collide, producing B mesons and anti-B mesons in equal amounts. The science goal of the B factories is to study CP violation in B meson decay, which may shed light on why the universe contains more matter than antimatter.