Hamburg 2016 – scientific programme
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T: Fachverband Teilchenphysik
T 84: Trigger und DAQ III
T 84.4: Talk
Wednesday, March 2, 2016, 17:30–17:45, VMP11 HS
Electrons and photons at High Level Trigger in CMS for Run II — •Afiq Anuar1 and Matteo Sani2 — 1DESY, Hamburg — 2UCSD, San Diego
The CMS experiment has been designed with a 2-level trigger system. The first level is implemented using custom-designed electronics. The second level, the High Level Trigger (HLT), is a streamlined version of the CMS offline reconstruction software running on a computer farm. For Run II of the Large Hadron Collider, the increase in center-of-mass energy and luminosity will raise the event rate to a level challenging for the HLT algorithms. New approaches have been studied to keep the HLT output rate manageable while maintaining thresholds low enough to cover physics analyses. The strategy mainly relies on porting online the ingredients that have been successfully applied in the offline reconstruction, thus allowing to move HLT selection closer to offline cuts. Improvements in HLT electron and photon definitions will be presented, focusing in particular on: updated clustering algorithm and the energy calibration procedure, new Particle-Flow based isolation approach and pileup mitigation techniques, and an electron-dedicated track fitting algorithm based on Gaussian Sum Filter.