The Phase-2 Upgrade of the CMS Outer Tracker

The Large Hadron Collider\,(LHC), at CERN will undergo major upgrades to be able to deliver peak instantaneous luminosities of about $5-7.5\times 10^{34}~\mathrm{cm}^{-2}\mathrm{s}^{-1}$ by 2027. This High Luminosity upgrade of the LHC (HL-LHC) is expected to deliver a total of about $3000-4000~\mathrm{fb}^{-1}$ during ten years of operation. At the nominal instantaneous luminosity of the HL-LHC, a single bunch crossing will produce $140-200$ proton-proton collisions. The current CMS strip tracker and the CMS Phase-1 pixel detector will not be able to survive the harsh operating conditions of the HL-LHC period. The CMS experiment will install a new silicon tracker for the HL-LHC. The Phase-2 Outer Tracker\,(OT) will feature increased radiation hardness, higher granularity and track separation and compatibility with higher data rates and a longer trigger latency. In addition, the OT will provide tracking information to the Level-1 trigger, allowing trigger rates to be kept at a sustainable level without sacrificing physics potential. To achieve this, the OT will be made up of modules with two closely spaced sensors read out by a single ASIC. The ASIC will correlate data from both sensors to form short track segments called stubs, to be used in tracking at Level-1. In this contribution, the design of the CMS Phase-2 OT, the technological choices and highlights of the research and development activities will be reported.