Tracking Triggers for the HL-LHC

TL;DR

This paper reviews the development and plans for hardware-based track reconstruction in CMS and ATLAS trigger systems for the High-Luminosity LHC, highlighting challenges, options, and expected performance improvements.

Contribution

It provides a comprehensive overview of the planned track trigger systems for HL-LHC, comparing CMS and ATLAS approaches and discussing their challenges and expected capabilities.

Findings

CMS track trigger will significantly improve event selection.

Different strategies are being considered for CMS and ATLAS.

Expected performance enhancements for trigger efficiency and accuracy.

Abstract

Hardware-based track reconstruction in the CMS and ATLAS trigger systems for the High-Luminosity LHC upgrade will provide unique capabilities. An overview is presented of earlier track trigger systems at hadron colliders, in particular for the Tevatron CDF and D0 experiments. We discuss the plans of the CMS and ATLAS experiments to implement hardware-based track reconstruction for the High-Luminosity LHC. Particular focus is placed on the track trigger capability of the upgraded CMS experiment. We discuss the challenges and opportunities of this novel handle, and review the alternatives that were considered for its implementation as well as discuss the expected performance. The planned track trigger systems for CMS and ATLAS have different goals, and we compare and contrast the two approaches.