Speaker
Description
The first level of the LHCb experiment’s trigger system (HLT1) performs real-time reconstruction and selection of events at the LHC bunch crossing rate using GPUs. It must balance the diverse goals of the LHCb physics programme, which spans from kaon physics to the electroweak scale.
To maximise the physics output across the entirety of LHCb's physics programme, an automated bandwidth division has been deployed since 2024. This procedure uses adaptive moment estimation to determine the optimal selection criteria while satisfying constraints such as the total HLT1 output rate and thresholds shared between common trigger categories.
The bandwidth division is now widely available to the collaboration for development and testing of new trigger lines via Continuous Integration (CI) on GitLab, providing information about exclusive and inclusive rates per trigger line, trigger efficiencies for each simulation sample included, and inclusive rate overlap between trigger lines. A near term goal is to develop the bandwidth division CI into allowing pseudo-real-time tunings. This will enable the end-users to study and monitor the effect of selection criteria on the trigger rate under realistic conditions for the study and monitoring of trigger performance.
This talk will present the bandwidth division algorithm, its place in the LHCb real-time analysis paradigm, and the development towards having a pseudo-real-time bandwidth division for LHC Run 4 and onwards using continuous integration and automation.