Dynamic beam-beam effects measured at KEKB

A series of measurements were carried out to investigate the dynamic beam-bearn effects. The beam-beam kick and the beam-bearn tune-shift were obtained by comparing the beam parameters between a colliding bunch and a non-colliding one. The horizontal beam size at the interaction point estimated from a beam-bearn kick curve slightly decreased as the beam-beam parameter increased. The horizontal emittance estimated from the beam-beam tune shift was larger than an unperturbed emittance and agreed with calculated emittance using a higher-mode tune. A ratio of the beta function between two locations in the ring, however, showed a big disparity between measured values and a calculation.