Pileup Removal Algorithms

One of the main challenges of the upcoming LHC run will be the increase of instantaneous luminosity, which will result in a large number of additional proton-proton collisions in each event (pileup). In such a high pileup environment, the accurate reconstruction of jet properties and shapes will be more and more demanding. In this note, the performances of various advanced pileup mitigation tools such as charged hadron subtraction, grooming techniques, jet cleansing and per particle pileup approaches are studied. The focus is on preparation for LHC Run II for which we expect up to 40 additional pileup events on average and includes comparisons to LHC Run I data which has typically 20 additional pileup events on average.