Studies of the impact and mitigation of pile-up on large-$R$ and groomed jets in ATLAS at $\sqrt{s}=7$ TeV

Large radius jets provide one avenue towards efficient reconstruction of massive boosted objects whose decay products are sufficiently collimated so as to make standard reconstruction techniques impractical. The potentially adverse impact of additional proton-proton interactions on such large jets is assessed for a variety of jet types and hadronic final state topologies. The mitigation of these effects via jet grooming algorithms such as trimming, pruning, and filtering is then studied for high transverse momentum jets at $\sqrt{s}=7$ TeV using an integrated luminosity of 4.7 fb$^{-1}$ collected with the ATLAS detector. A total of 29 jet algorithms and grooming configuration combinations are studied. The application of jet trimming and filtering significantly improves the robustness of large-$R$ jets and reduces their sensitivity to the intense environment of the high-luminosity LHC. The consequence is an overall improvement in the physics potential of searches for heavy boosted objects.