Diffractive and exclusive measurements at CMS

Recent measurements are discussed of inclusive and exclusive diffractive processes in pp colli- sions at √ s = 7 TeV at the LHC using the CMS detector. Results are presented of the single- and double-diffractive cross section and of the inclusive differential cross section for events with a forward rapidity gap. A study of exclusive W + W − production by two-photon exchange, where, in different kinematic regions, both con fi rmation and deviations from the Standard Model predic- tions are searched, is reported. Finally, a joint measurement with the CMS and TOTEM detectors of the pseudorapidity distribution of charged particles produced in pp collisions at √ s = 8 TeV is presented. This is the fi rst joint study between the two experiments

Triggering on Forward Physics

The feasibility is investigated of a dedicated trigger stream in the CMS trigger menu, with an output rate of cal O (1)~kHz on the First Level Trigger and cal O (1)~Hz on the High Level Trigger. By combining jet trigger information from the CMS calorimeter with information from the TOTEM Roman Pot detectors at 220 m distance from the interaction point, the default dijet trigger thresholds foreseen in the CMS trigger tables can be lowered substantially while respecting the CMS trigger bandwidth limits. The efficacy of the dedicated diffractive trigger stream is demonstrated for hard single-diffractive and double-Pomeron exchange events

Intrinsic time resolution of 3D-trench silicon pixels for charged particle detection

In the last years, high-resolution time tagging has emerged as the tool to tackle the problem of high-track density in the detectors of the next generation of experiments at particle colliders. Time resolutions below 50ps and event average repetition rates of tens of MHz on sensor pixels having a pitch of 50$\mu$m are typical minimum requirements. This poses an important scientific and technological challenge on the development of particle sensors and processing electronics. The TIMESPOT initiative (which stands for TIME and SPace real-time Operating Tracker) aims at the development of a full prototype detection system suitable for the particle trackers of the next-to-come particle physics experiments. This paper describes the results obtained on the first batch of TIMESPOT silicon sensors, based on a novel 3D MEMS (micro electro-mechanical systems) design. Following this approach, the performance of other ongoing silicon sensor developments has been matched and overcome, while using a technology which is known to be robust against radiation degradation. A time resolution of the order of 20ps has been measured at room temperature suggesting also possible improvements after further optimisations of the front-end electronics processing stage.Comment: This version was accepted to be published on JINST on 21/07/202