Study of beam-beam interaction with a large Piwinski angle at LHC

Collision with a large Piwinski angle is one of the update scenarios of LHC toward the luminosity 1035 cm−2s−1. The large Piwinski angle is realized by a small beta function at the collision point and longer bunch length. The Piwinski angle is increased from 0.6 to 2 in the scenario. The bunch population is increased so as to keep the beam-beam parameter. The beam-beam performance is degraded by crossing angle which induces additional nonlinear terms due to a symmetry breaking of the collision especially for the high beam-beam parameter. Effect of crossing angle for the nominal LHC design and the large Piwinski angle scheme are studied.