Characteristics of beam collision timing and position at the KEK B-factory

Using the Belle detector we study the characteristics of beam collisions at the KEKB 3.5 GeV e+ and 8 GeV e− asymmetric energy collider. We investigate the collision timing tIP and its z-coordinate along the beam axis zIP as a function of the position of the colliding bunch in a beam train. The various tIP and zIP behaviors observed by Belle are attributed to beam loading effects in the radio frequency cavities that accelerate the beams with a beam abort gap. We also discuss the prospects for the Super-KEKB collider.