Precision tIming in the quest for New physiCs at LHC

L'obiettivo del progetto PINCH è quello di dimostrare l'importanza dei rivelatori per la misura del tempo di volo nel ricerca di nuova fisica ai collisionatori di particelle. La realizzazione del progetto in questo momento storico, a pochi anni dall'inizio della presa dati di HL-LHC, aumenterà in modo rilevante il potenziale scientifico di scoperta delle analisi dei dati ad LHC.

The PINCH project intends to design a novel approach in the investigation of physics Beyond the Standard Model at the Compact Muon Solenoid (CMS) experiment for the High Luminosity phase of LHC (HL-LHC). The leading thread of the project is the possibility to exploit precise timing information to reconstruct, in the prohibitive environment of multiple interactions of HL-LHC, non conventional signatures usually discarded by standard algorithms. The expectation to observe “exotic” behaviors in LHC data is strongly supported by conceptual and experimental facts that cannot be explained within the Standard Model itself. Directly searching for unusual final states allows us to discover what we do not know yet about Beyond the Standard Model physics. A hot topic are models which predict the existence of long-lived particles which travel inside the detector before decaying to standard particles. The HL-LHC program is expected to start in 2029, based on a major improvement of the accelerator to increase the instantaneous luminosity by a factor of 10. To cope with the multiple collisions belonging to the same bunch crossing, the CMS collaboration has implemented an upgrade program based on higher detector granularity to reduce single-channel occupancy, improved trigger capabilities and bandwidth for data acquisition, and use of timing information to correctly assign charged tracks and neutrals to the primary collision. The latter upgrade foresees the use of timing from the calorimeters and the installation of specialized detectors dedicated to minimum ionizing particles, equipping, for CMS, the whole solid angle. The advantages arising from the inclusion of 30-40 ps precision timing in the online selection will be explored, as a unique opportunity to access for the first time signatures with characteristic time structures at CMS. We will further investigate the deployment of particle timing measurement as a key ingredient to enhance analysis capabilities in the harsh environment of HL-LHC. A set of benchmark models will be considered predicting final states with long-lived particles. For a robust assessment of performance, a detailed understanding of the detector time resolution is fundamental. PINCH plans to build a prototype with state-of-the-art timing detectors and study its performance in a test beam complementing it with irradiation studies. The four-years-long LHC Run 3, starting in 2022, offers a unique opportunity to prepare the ground for this project, thanks to the lower instantaneous luminosity compared to the HL-LHC and the possibility to exploit timing information from already existing calorimeters to test novel algorithms and approaches both online and offline. The goal of the project is to demonstrate the relevance of timing detectors in the quest for new physics at colliders. The realization of the project now, a few years before the starting of the HL-LHC, will timely boost the scientific potential of data analysis at LHC.