Identification of boosted, hadronically decaying W bosons and comparisons with ATLAS data taken at $\sqrt{s} = 8$ TeV

This paper reports a detailed study of techniques for identifying boosted, hadronically decaying W bosons using 20.3 fb$^{-1}$ of proton–proton collision data collected by the ATLAS detector at the LHC at a centre-of-mass energy $\sqrt{s} = 8\,\mathrm{TeV}$ . A range of techniques for optimising the signal jet mass resolution are combined with various jet substructure variables. The results of these studies in Monte Carlo simulations show that a simple pairwise combination of groomed jet mass and one substructure variable can provide a 50 % efficiency for identifying W bosons with transverse momenta larger than 200 GeV while maintaining multijet background efficiencies of 2–4 % for jets with the same transverse momentum. These signal and background efficiencies are confirmed in data for a selection of tagging techniques.