May 16 – 20, 2022
Europe/Zurich timezone

Studies of the long term stability of track selection criteria for the ATLAS track counting luminosity measurement

May 17, 2022, 7:00 PM
Experimental poster Performance and Tools Poster Session I


Thomas Christopher Mclachlan (Deutsches Elektronen-Synchrotron (DE))


A precise measurement of the luminosity is an essential part of the ATLAS physics program and is of particular importance to cross-section measurements, where it can be one of the largest systematic uncertainties. The track-counting method is one of several approaches used within ATLAS to compute the luminosity and involves counting the number of charged-particle tracks reconstructed in the Inner Detector. The average number of tracks scales linearly with the number of simultaneous proton-proton interactions, µ, per bunch-crossing, and can therefore be used to measure the luminosity.

This poster presents studies of the long term stability of the track-counting luminosity measurement in the LHC Run 2. Different track selection criteria are studied and are compared on a run-by-run basis, providing insights on changing detector conditions and beam configurations throughout each data-taking year. In addition, events from Z—>µµ decays are used to test the efficiency of the track selections and to study the stability over time.

Primary authors

Collaboration ATLAS Junjie Zhu (University of Michigan (US)) Sandra Leone (Universita & INFN Pisa (IT))

Presentation materials