Calculation of Higher Order Modes and Wakefields for the Vacuum Chamber of the CMS Experiment at the LHC

The trapped Higher Order Modes in the vacuum chamber of the CMS experiment at the LHC have been investigated using a geometrical model which closely reflects the presently (in 2008) installed vacuum chamber. The basic rf-parameters of the higher order modes (HOMs) including the frequency, loss parameter, G1 and the Q-value together with extensive graphical representations of the longitudinal electrical fields are provided. To also cover transient effects the short range wakefieds and the total loss parameter have been calculated, too. Most numerical calculations have been performed with the computer code MAFIA. The obtained data are intended to be include into the impedance database of the LHC.