The BES - III experiment at the high luminosity Tau - Charm factory

In early 80’s, Chinese government decided to build an ee collider running at the tau-charm energy region, called BEPC, which is completed in 1989. The only detector at the machine is called Beijing spectrometer(BES). In mid 90’s, there has been a minor upgrade of the detector, which is then called BESII. Since then, hundreds of papers have been published on the international journals, some with significant impacts to the community. The upgrade of BEPC was decided at the beginning of this century, called BEPCII, which has a designed luminosity of 10 cms, an increase of a factor of 100. The corresponding detector, called BES-III, adopted latest detector technology to minimize systematic errors in order to match the unprecedented statistics. The physics program of the BES-III experiment includes light hadron spectroscopy, charmonium, electroweak physics from charmed mesons, QCD and hadron physics, tau physics and search for new physics. Due to its huge luminosity and small energy spread, the expected event rate per year is historical, as listed in table I.