On the measurement of W to 3 pi with the Phase 2 L1 scouting system at CMS

The aim of this master's thesis project is to demonstrate the feasibility of an online selection process for the phase 2 scouting system at CMS. The focus is on a rare decay of W to 3 pi particles, which forms the basis of the selection process. The initial phase involves a concise analysis with the objective of establishing an upper limit on the branching fraction for the decay of the W boson. To achieve this, Monte Carlo simulations of the Phase 2 scouting data are utilized, providing valuable insights into the feasibility of the selection. Then, a firmware algorithm is developed to emulate the data flow of particles from the correlator layer of the phase 2 L1 Trigger configuration. This algorithm is specifically designed to operate on the trigger board, thereby enhancing the efficiency and effectiveness of the process. Once the firmware algorithm is implemented, the data flow path is set up. The particles generated in the trigger board are transmitted to the Data Transmission Hub (DTH) and subsequently acquired in the PC. Here, the raw data is unpacked, allowing for the construction of a N-tuple for further analysis. The final step involves the actual analysis selection performed on the acquired data. This step represents the culmination of the project's efforts and aims to optimize the selection process as much as possible. Each step in the path is thoroughly investigated and tailored for maximum efficiency. In particular, careful attention is given to assessing the latency of each step to determine if the analysis selection's working rate aligns with the LHC's operating frequency of 40MHz and specifically, with the data acquisition rate of the scouting system.