Precision Proton Spectrometer timing detector efficiencies and two-arm timing resolution in 2018 data

The Precision Proton Spectrometer (PPS) is a forward-proton spectrometer using near-beam detectors (inside Roman Pots, RPs) located symmetrically on both sides of IP5 at a distance of about 220 m. In addition to the tracking system, timing detectors were installed in 2017 to measure the Time-Of-Flight (TOF) of the protons produced in central exclusive interactions. Two cylindrical RPs were equipped with Diamond sensors. In 2018 the TOF system consisted of two single- and two double-diamond planes. This note describes the timing-track efficiency of the sensors in low and high luminosity runs and the resolution of the timing system in two-arm events. Using low pileup data ($\mu$ = interactions/crossing = 1) and selecting central diffractive events a strong correlation is observed between the time difference of the protons detected in PPS, and the longitudinal vertex position reconstructed in the central CMS tracker.