Calculation of Wakefields and Higher Order Modes for the New Design of the Vacuum Chamber of the CMS Experiment for the HL-LHC

To extend the discovery potential of the Large Hadron Collider (LHC) a design study for a novel machine configuration, the High Luminosity LHC (HL-LHC), was started with the goal to increase its luminosity by a factor of 10 beyond its design value. The new machine configuration will also include an upgraded detector configuration and a new beam pipe in the CMS detector. The short range wakefields and the trapped Higher Order Modes (HOMs) for the new design of the vacuum chamber are calculated and compared with the presently used chamber. The kick and loss parameters are presented for different sets of beam parameters. The numerical calculations have been performed with the computer codes MAFIA and ECHO2D. The obtained data are intended to be included into the impedance database of the HL-LHC.