Denys Wilkinson Building, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH
Mark Owen, University of Glasgow
Abstract
The top quark mass is one of the key fundamental parameters of the Standard Model that must be determined experimentally. Its value is essential for testing the self-consistency of the Standard Model. This seminar presents a new measurement of the top quark mass conducted by ATLAS using the full Run 2 LHC proton-proton dataset at 13 TeV. The measurement targets top-antitop-quark pair events where the hadronically decaying top quark has high transverse momentum and is reconstructed as a large-radius jet. A simultaneous fit is performed to the mean of the invariant mass of the large-radius jets and two additional kinematic observables that target the reduction of systematic uncertainties relating to the Jet Energy Scale and Monte Carlo modelling. This results in the most precise ATLAS top quark mass measurement from a single channel to date, with a total uncertainty of 0.53 GeV.