Task 3.4: Optimal Calibrations for HLT

Task lead:
Thiago Tomei (SPRACE & São Paulo State University)

Task members:
Andrea Bocci (CERN), Marco Musich (CERN), Jessica Prendi (CERN, ETH Zürich), Mateusz Zarucki (CERN)

The Next Generation Triggers (NGT) project aims to rethink the CMS experiments trigger system strategy for the Phase-2 upgrade of the HL-LHC and beyond. The Real-time Reconstruction Revolution (R3) initiative aims to bring offline-quality event reconstruction into the High-Level Trigger (HLT) filtering system in real-time. By buffering the entire HLT input stream and applying higher quality calibrations online during data taking, the system can deliver compact, analysis-ready events with the accuracy required for high-quality physics analysis.

NGT Demonstrator

To demonstrate feasibility, NGT deployed a prototype system within the CMS data-acquisition infrastructure during LHC Run 3. The system buffers a small fraction (≈ 1%) of trigger data for several hours, allowing precise calibrations to be computed during this time window and applied before HLT reconstruction. The system is fully validated using standard data-quality monitoring, demonstrating that high-quality, calibration-aware reconstruction can be achieved directly within the trigger workflow.

The operation of the NGT demonstrator is showcased through a live view of its dedicated DAQ monitoring instance. The recording illustrates how buffered data coming directly from the CMS detector are reprocessed by the NGT demonstrator after several hours using newly-derived detector calibrations.

Publications and other resources