July 28, 2020 to August 6, 2020
virtual conference
Europe/Prague timezone

Luminosity Determination using Z->ll Counting for Run-2 ATLAS Data

Jul 29, 2020, 1:48 PM
virtual conference

virtual conference

Poster 12. Operation, Performance and Upgrade of Present Detectors Operation, Performance and Upgrade of Present Detectors - Posters


Michael William O'Keefe (University of Liverpool (GB))


During Run 2, LHC delivered instantaneous luminosities of $\approx 10^{34}$ cm$^{-2}$ s$^{-1}$ at $\sqrt{s}=13\; {\rm TeV}$. This permitted monitoring of the luminosity over a time granularity as short as $60\;{\rm s}$, using the counts of $Z\rightarrow \ell \ell$ events reconstructed by selecting two, well-idenfitied high $p_T$ electrons or muons in the invariant mass range of $66 < m_{\ell \ell} < 116$ GeV.

The poster illustrates the measurement principles based on time-dependent trigger and reconstruction efficiency corrections and shows the stability of using both $Z\to ee$ and $Z\to \mu \mu$ boson counting as luminometers. Emphasis is given to illustrate with selected LHC run examples the robustness of the method with respect to pile-up and the LHC bunch structure, which are of particular importance for reliable luminosity monitoring at the upcoming high luminosity phase of the LHC.

Primary author

Michael William O'Keefe (University of Liverpool (GB))

Presentation materials