Precision Timing with the CMS MIP Timing Detector for HL-LHC

The Compact Muon Solenoid (CMS) detector at the CERN Large Hadron Collider (LHC) is undergoing an extensive Phase II upgrade program to prepare for the challenging conditions of the High-Luminosity LHC (HL-LHC). A new timing detector in CMS will measure minimum ionizing particles (MIPs) with a time resolution of 30-40 ps for MIP signals at a rate of 2.5 Mhit/s per channel at the beginning of HL-LHC operation. The precision time information from this MIP Timing Detector (MTD) will reduce the effects of the high levels of pileup expected at the HL-LHC, bringing new capabilities to the CMS detector. The MTD will be composed of an Endcap Timing Layer (ETL), instrumented with Low-Gain Avalanche Detectors, as well as a Barrel Timing Layer (BTL) based on LYSO:Ce crystals coupled to SiPMs. In this talk we will present overview of the MTD, focusing on recent prototyping results and R&D studies targeting enhanced timing performance and radiation tolerance.