Advancements in Particle Tracking Technology for CMS Phase-2 Upgrade

Recent tests conducted on prototypes of the CMS Phase-2 Outer Tracker module have demonstrated significant advancements in particle tracking technology. The study, titled "Beam Test Performance Studies of CMS Phase-2 Outer Tracker Module Prototypes," was authored by the Tracker Group of the CMS Collaboration and is available on arXiv (arXiv:2404.08794).

The CMS (Compact Muon Solenoid) detector is undergoing a major upgrade to enhance its capabilities for the high-luminosity era of the Large Hadron Collider (LHC). This upgrade includes the installation of a new tracking detector, which features an Inner Tracker with silicon pixel sensor modules and an Outer Tracker composed of modules with two parallel stacked silicon sensors.

During tests held at the Test Beam Facility in Hamburg from 2019 to 2020, seven prototypes of the Outer Tracker modules were evaluated. These modules incorporate the CMS Binary Chip (CBC) and the Concentrator Integrated Circuit (CIC), which facilitate the optical readout and power conversion on the module itself. One of the modules tested was assembled with sensors that had been irradiated with protons, allowing for a comprehensive assessment of their performance.

The results indicated a cluster hit efficiency of approximately 99.75% across all tested modules, confirming the synchronous readout capability of the modules. Furthermore, the pT discrimination mechanism, which is crucial for correlating hits from charged particles, was verified to function effectively with the new technology. These findings suggest that the performance of the modules meets the operational requirements for the upgraded CMS tracking detector, which is essential for future experiments at the LHC.

This research not only contributes to the ongoing development of particle physics but also enhances the precision of measurements that can be made in high-energy collisions, potentially leading to new discoveries in fundamental physics.