Like all experimental groups around the world, the Belle collaboration at Japan’s KEK laboratory is always pushing for higher luminosity, and for the past couple of years the KEKB accelerator team has responded with successive improvements both in hardware and in beam tuning. The latest achievement came in October 2002, when Belle had accumulated an integrated luminosity of 100 fb-1 – a tally that no single collider experiment has previously achieved.
At the same time, KEKB notched up several milestones itself, with a beam current in the high-energy (electron) ring of 1006 mA, a peak luminosity of 82.56 ¥ 1032 cm-2 s-1, and integrated luminosities of 149.1 pb-1 in an 8 h shift and 433.7 pb-1 in a day. These numbers show that KEKB is still steadily progressing towards its design luminosity of 1034 cm-2 s-1.
The teams from KEKB and Belle, together with many others, celebrated these achievements on 28 October, and were toasted by two Nobel prize winners – Professor Masatoshi Koshiba, who shared last year’s Nobel Prize for Physics, and Professor Burton Richter, who won the prize in 1976 and was visiting KEK.
