Expected Tracking Performance of the ATLAS Inner Tracker at the High-Luminosity LHC

TL;DR

This paper evaluates the expected tracking performance of the new ATLAS Inner Tracker (ITk) at the High-Luminosity LHC, demonstrating its readiness to handle increased collision rates and improve particle trajectory reconstruction.

Contribution

It provides the first detailed performance assessment of the upgraded ATLAS Inner Tracker using recent developments and simulations for high-luminosity conditions.

Findings

ITk achieves high tracking efficiency in simulated HL-LHC conditions

Track reconstruction performance exceeds current detector capabilities

The software adaptation enables effective operation in high pile-up environments

Abstract

The high-luminosity phase of LHC operations (HL-LHC), will feature a large increase in simultaneous proton-proton interactions per bunch crossing up to 200, compared with a typical leveling target of 64 in Run 3. Such an increase will create a very challenging environment in which to perform charged particle trajectory reconstruction, a task crucial for the success of the ATLAS physics program, and will exceed the capabilities of the current ATLAS Inner Detector (ID). A new all-silicon Inner Tracker (ITk) will replace the current ID in time for the start of the HL-LHC. To ensure successful use of the ITk capabilities in Run 4 and beyond, the ATLAS tracking software has been successfully adapted to achieve state-of-the-art track reconstruction in challenging high-luminosity conditions with the ITk detector. This paper presents the expected tracking performance of the ATLAS ITk based on the latest available developments since the ITk technical design reports.