BEPCII and BESIII

The Beijing Electron Collider is being upgraded (BEPCII) to a two-ring collider with a design luminosity of at a center-of-mass energy of 3.89 GeV. It will operate between 2 and 4.2 GeV in the center of mass. With this luminosity, the BESIII detector will be able to collect, for example, 10 billion J/ψ events in one year of running. This will be a unique facility in the world opening many physics opportunities. BEPCII and BESIII are currently under construction, and commissioning of both is expected to begin in summer 2007.