Tracking and b-Tagging Performance with an Upgraded CMS Pixel Detector

The luminosity upgrade of the Large Hadron Collider is foreseen to proceed in two phases. An increased luminosity of 2×1034cms-1s-1, is planned for the first phase of the upgrade, called HL-LHC Phase 1. Tracking and identificationofjets originating frombquarks (b-tagging) will continuetobeakeyelementof manyphysics analyses at the upgraded HL-LHC where much higher pileup can significantly reduce the performance. An upgrade of the CMSpixel detector proposedforthe Phase1HL-LHC should enableCMSto maintainthe currentlevelof b-tagging performance even in the presence of very high pileup. We present simulation studies of the proposed baseline Phase 1upgrade pixel detector for tracking and b-tagging performance compared to that for the current CMS detector.