Phase I and Phase II CMS upgrade

The LHC experiments have recently completed a very successful multi-year run, culminating with the discovery in 2012 of a Higgs Boson with a mass near 126 GeV. The accelerator and experiments are currently in a long shutdown, LS1, preparing for the next round of operations at nearly twice the beam collision energy up to 14 TeV with 25 ns bunch spacing. With the upgrades planned for the accelerator complex, the luminosity is expected to increase to over twice the original LHC goal of 1 × 1034 cm−2 s−1 this decade, and finally to 5 × 1034 cm−2 s−1 with HL-LHC early next decade. Such high luminosities pose challenges to the detectors. The presentation will summarize the upgrade plans for CMS to meet these challenges. The first phase, to be completed by the second long shutdown, LS2, includes a new pixel detector and upgrades to the hadron calorimeter, muon and trigger systems. A second phase, preparing for HL-LHC operation in LS3, will include a new tracking system and upgrades to the forward calorimeters. With these upgrades CMS can look forward to a rich and exciting physics programme.