Computer simulation of the coherent beam-beam effect in the LHC

For the Large Hadron Collider (LHC) in the Large Electron-Positron Colliding Beam Accelerator (LEP) tunnel, a nonzero crossing angle is foreseen to avoid multiple collisions outside the interaction point. The coherent dipole oscillations induced by long-range beam-beam interactions for the LHC have been investigated. The two beams can suffer from long range beam-beam interactions during the time they are in one common vacuum chamber. These long range interactions can excite coherent beam-beam modes, and, due to the finite separation, they are in general nonlinear, leading to possible coherent resonances of a higher order. A computer simulation has been developed and was used to investigate this coherent beam-beam effect. Possible constraints on the LHC parameters are investigated and discussed.<>