Crab-Crossing and Luminosity Simulations J.W. Flanagan, KEK

SuperKEKB Parameters w/wo Crab Crossing Weak-Strong Simulation Strong-Strong Simulation e35

Luminosity Luminosity: Beam-beam parameters: Energy transparency:

Luminosity Reduction Factor Hirata Formula: F(emittance, beta, crossing angle, bunch length)

Simulation: Crab-Crossing Crab-crossing restores full luminosity of a head-on collision. (S-S)

Ohmi Simulations For crossing angle > 10 mrad both W-S and S-S show vertical beam-beam parameter saturating at ~0.06. At zero crossing angle, W-S and S-S disagree.

SuperKEKB Parameters w/wo Crab Crossing Weak-Strong Simulation Strong-Strong Simulation e e35