SuperKEKB is a positron-electron collider with a nano-beam scheme. The nano-beam scheme allows the extremely low beta function at the interaction point (IP) compared to the bunch length, namely ordinary colliders. The beta function at the IP is less than 1 mm which is the smallest value among the previous colliders. Recent results on beam-beam interactions, beam injection under the influence of beam-beam interactions, and a performance of the crab-waist scheme that improves the luminosity performance are discussed. Sudden beam loss (SBL), which cannot be explained by usual beam dynamics, and the nonlinear collimator as a key device to reduce both beam background and impedance are also crucial issues. We present the recent machine operation and performance of SuperKEKB which predicts the future high energy and luminosity colliders.
Yukiyoshi Ohnishi (Thu,) studied this question.