Towards a precise measurement of particle time-of-flight with the new MIP Timing Detector with the CMS experiment

The design and primary use cases of the novel MIP Timing Detector (MTD), introduced by the CMS experiment for its High-Luminosity Large Hadron Collider (HL-LHC) Phase-II upgrade, are here described. The strategy for its application to 4D vertex reconstruction is outlined, with a focus on the latest developments in uncertainty estimation. The introduction of a new source of uncertainty on track times, namely particle time of flight uncertainty, is discussed, along with its estimation strategy and comparison to MTD uncertainty. This additional contribution is non-negligible for low-momentum heavy particles, such as protons with p less than or similar to 2 GeV; however, impact on final vertex performance has been found to be minimal.