Key performance measures towards real time tracking for the CMS detector at High Luminosity LHC

The increased instantaneous luminosity of 5 × 1034 cm−2s−1 to be provided by the upgrade of the LHC (High Luminosity LHC) by 2028, will open unprecedented opportunities for the high precision study of the Standard Model of particle physics and for searches of physics beyond the Standard Model. To exploit such an opportunity, and to address the challenges of an increased pile up condition of 200 events per bunch crossing , the CMS experiment will upgrade most of its subdetectors. In particular, a completely new tracker detector is being developed. One of the most innovative designs consists of a new sensor concept called module. The module filters out hits produced by low transverse momentum tracks directly on the front end electronics. In such a way the data rate is brought to a manageable level to allow online track reconstruction at the collision rate of 40 MHz within a latency of only 5 s, with dedicated processors based on FPGA. The online reconstructed tracks will be sent to the Level 1 trigger boards, where high level objects will be formed, such as vertices, and, together with the information from other subdetectors, more complex objects, such as muons, electrons, jets, missing energy etc. This thesis deals with the measurement of some of the key aspects that must be fulfilled in order to achieve the desired on- line track reconstruction efficiency, and that I had the possibility to perform. The first part is devoted to the measurement of the latency of several blocks of the online tracking system: the one coming from the optical fibre length, as measured by an ad-hoc developed setup, and the one from the track finding algorithm run on the FPGA. The second part is devoted to measure the per- formances of the modules in terms of efficiencies and tracking precision, after having developed an alignment algorithm in a test beam with 160 GeV muons performed at CERN, which I took part during the Fall of 2022