Prospects for Upgrade of KEKB

The Belle experiment at the KEKB electron-positron collider is expected to have collected close to one billion ϒ(4S) events by the time it comes to an end in 2009. An upgrade to KEKB has been proposed. It is designed for an order of magnitude higher luminosity than KEKB, following a three-year construction period. The ultimate goal of 8×1035cm−2s−1 luminosity would be reached through further improvements over several years. To exploit the physics accessible through this improved luminosity, an upgrade of the Belle detector is also planned. A new international collaboration, temporarily named sBelle, is in the process of being formed. Super-KEKB and sBelle were officially placed on the KEK 5-year Roadmap in early 2008.