THE CMS SILICON TRACKER AT LHC

Abstract The paper describes the Silicon Tracking System of the Compact Muon Solenoid (CMS) experiment that is foreseen to collect events from p–p collision at the E cm =14 TeV at the CERN future Large Hadron Collider (LHC). The proposed system consists of four layers of silicon microstrip detectors placed between the two inner layers of the pixel detector and the outer microstrip gas chamber system. The barrel part covers the η region up to 1.8, instrumenting the central radial region between 20 and 50 cm. The forward–backward disks extend the coverage up to η =2.6. This paper will review the main characteristics and performances of the system, the actual status of the R&D activities that we are carrying on, and the status of the milestones we have to fulfill in view of the Technical Design Report expected at the end of the year.