Measurement of the ATLAS Detector Jet Mass Response using Forward Folding with 80 $\text{fb}^{-1}$ of $\sqrt{s}=13$ TeV $pp$ data

This note reports a measurement of the jet mass response of large-radius jets reconstructed by the ATLAS experiment using $80~\mbox{fb\(^{-1}\)}~$of $\sqrt{s}=13~\text{TeV}~pp$ data. The response is defined as the distribution of the measured mass given the particle-level jet mass and is characterised by its central value (jet mass scale) and spread (jet mass resolution). In order to account for non-Gaussian behavior of the response as well as non-trivial contributions from the intrinsic particle-level jet mass probability density, the forward-folding method is chosen for the measurement. This procedure is applied to both a top-quark pair final state (200 GeV<$p_\text{T}$<600 GeV for $W$ boson jets and 350 GeV <$p_\text{T}$<1000 GeV for top-quark jets) as well as inclusive $W/Z$+jets events (500 GeV<$p_\text{T}$<1200 GeV). Results are presented for trimmed anti-$k_t$ $R=1.0$ jets built using only calorimeter information as well as for the track-assisted jet mass that combines calorimeter and tracker information, and for reclustered small-radius jets also using $R=1.0$. This note extends previous results by including more data, incorporating the $W/Z$+jets final state, and by comparing various jet mass definitions. In addition, the jet mass response is studied for different numbers of subjets within reclustered jets and found to be universal. For both the jet mass scale and jet mass resolution, good agreement is observed between the data and simulated samples. Uncertainties are evaluated to be 1--5\% for the scale and 10--20\% for the resolution and they are driven by the parton shower and hadronisation modelling.