Luminosity determination in $pp$ collisions at $\sqrt{s}=13$ TeV using the ATLAS detector at the LHC

This note describes the preliminary determination of the integrated luminosity for $pp$ collisions at $\sqrt{s}=13$ TeV recorded by the ATLAS detector during Run 2 of the LHC from 2015-2018. The absolute luminosity scale was determined using van der Meer scans during dedicated running periods in each year, and extrapolated to the physics data-taking regime using complementary measurements from several luminosity-sensitive detectors. The total uncertainties on the integrated luminosities for each individual year of data-taking range from 2.0-2.4 %, and are partially correlated between years. After typical data-quality selections, the full Run 2 $pp$ data sample corresponds to an integrated luminosity of 139 fb$^{−1}$ , with an uncertainty of 1.7%.