R&D in preparation for an upgrade of CMS for the Super- Large Hadron Collider

Large Hadron Collider operation will continue until at least 2035, with the ever-increasing performance required from both the accelerator complex in order to provide useful statistical reach. The Compact Muon Solenoid detector will, in turn, require significant and comprehensive upgrades in order to maintain performance in the presence of much harsher conditions.

The upgrades described in this proposal are mandatory to allow scientific return from the LHC to continue in the long term. We propose a technically ambitious five-year project from 2019 that will deliver state-of-the-art tracking, calorimetry and trigger capabilities for the Compact Muon Solenoid. These improvements will permit an order of magnitude increase in the recorded data set, allowing measurement of Higgs couplings and self-couplings, and greatly enhanced sensitivity to physics beyond the Standard Model.

The design of the upgraded tracker and trigger systems will be closely linked from the start, and their performance must be optimised in parallel, since the requirements of triggering and precision tracking using the same sub-detector, potentially conflict. The Compact Muon Solenoid Tracker is a highly integrated electromechanical system, of which detectors providing trigger information must form a coherent part.