Performance assumptions based on full simulation for an upgraded ATLAS detector at a High-Luminosity LHC

This note documents the performance assumptions used for ATLAS physics projections presented at the 2013 ECFA HL-LHC workshop. Parametrisations are derived for the object selection efficiencies and resolutions for an upgraded detector at a High Luminosity LHC. These are based on full simulations of the Phase II upgraded detector with realistic levels of in-time and out-of-time pile-up. The upgraded tracker maintains the performance of the Run 1 detector even in the presence of high pileup, with improved muon momentum resolution and b-tagging performance.