CMS Phase 2 Upgrade Project

The Large Hadron Collider (LHC) at CERN will be the world's highest energy particle accelerator for the foreseeable future, and the only facility capable of investigating some of the highest priority topics in fundamental physics. The UK has made a substantial long-term commitment to the design, construction and operation of the CMS detector, one of the two general-purpose detectors at the LHC.

LHC operation will continue until at least 2035, with ever-increasing performance required from both the accelerator complex in order to provide useful statistical reach. The CMS 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 2025 that will complete deliver of state-of-the-art tracking, calorimetry and trigger capabilities for CMS. 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.