Performance studies of the Roman Pot timing detectors in the forward region of the IP5 at LHC

The detection of Central Diffractive (CD) events at high luminosity requires the measurement the time of flight of the leading protons in order to resolve the pileup contribution and reduce the beam-beam background. The studies reported in this note concern the optimization of the timing detectors read-out geometry and considerations on the trigger strategy to reduce the rate and increase efficiency and purity in CD events selection. The background expected in the timing detectors is evaluated directly on data and introduced in a simulation tuned in order to take into account the relevant cross sections measured by TOTEM. The full simulation of the signal, pileup and background allows the assessment of the requirements of the timing detectors, in terms of resolution and geometry, such to optimize the reconstruction of the CD events thus that the protons can be assigned to the appropriate central vertex reconstructed by the CMS central detectors. The studies are performed in both vertical and horizontal Roman Pots which will operate at different LHC beam conditions. The conclusion is that by considering ad-hoc configurations of timing detectors a rejection of the main background sources (pileup and beam-beam) is achievable and CD processes can be measured even in hostile environment.