Transverse wakefields due to asymmetric protrusions into a vacuum chamber

We analyze the effect of a wakefield caused by an asymmetric protrusion inside the accelerator vacuum chamber. The asymmetry leads to a transverse kick on the beam and an increase of the projected transverse beam emittance. Calculations are done for a model rectangular protrusion in a vacuum chamber of rectangular cross-section. Based on our analysis, numerical estimates are given for the SuperKEKB accelerator in KEK, Japan, and TLEP-W proposal at CERN.