DEPOLARIZATION AND BEAM-BEAM EFFECTS AT THE LINEAR COLLIDER

The clean environment of a lepton linear collider allows high-precision measurements for physics analyses. In or- der to exploit this potential, precise knowledge about the polarization state of the beams is also required. In this pa- per we concentrate on depolarization effects caused by the intense beam-beam interaction, which is expected to be the dominant source of depolarization. Higher-ordereffects, as well as critical analyses of the theoretical assumptions used in the past and theoretical improvements in the derivation of suitable equations, are given. Updates on existing sim- ulation programs are reported. Numerical results for the design of the International Linear Collider (ILC) are dis- cussed.