Speaker
Description
The Next Generation Triggers (NGT) initiative in CMS aims to enable the processing of all Level-1 Trigger accepted collisions for the HL-LHC. Central to this effort is the expansion of the High-Level Trigger (HLT) data scouting strategy, where events are reconstructed and stored in an analysis-ready format. This necessitates an in situ processing loop to derive high-quality calibration constants during data taking, as offline reprocessing is not possible. In order to showcase the feasibility of this plan, an NGT Demonstrator has been commissioned during LHC Run-3. We present the software implementation of a novel calibration loop for the NGT Demonstrator, and the design choices motivated by offline calibration infrastructure studies. The system architecture comprises three interacting Finite State Machines (FSMs) that automate the data flow through three intertwined processing cycles which follow CMS’s current Prompt Calibration Loop: incremental physics event reconstruction, aggregation of calibration statistics, and derivation of calibration constants. The final calibration constants are stored within a dedicated record in CMS’s conditions database to be consumed by the NGT Demonstrator. This enables a delayed re-HLT processing step with optimal calibrations after 8 hours of data buffering. Finally, by extending the existing infrastructure for online data quality monitoring in CMS for the HLT data scouting stream, we evaluate the effect of the rederived calibrations in the online reconstruction, demonstrating the improvement in the physics performance of the HLT event selection.