Pileup-per-particle identification: optimisation for Run 2 Legacy and beyond

Pileup mitigation techniques are important for performing physics analysis in high pileup scenarios, such as in the data recorded by the CMS Collaboration during Run 2 of the LHC. The pileup per particle identification (PUPPI) algorithm was commissioned with 13 TeV data. While PUPPI generally showed improved performance compared to the charge hadron subtraction (CHS) algorithm in many aspects, the initial version of PUPPI yielded worse jet energy resolution for high-$p_T$ jets. In order to improve this behaviour of PUPPI, a new tune was developed. The results of this new tune, the achieved jet energy resolution, efficiency and purity, pileup jet rate, and the impact on jet substructure variables and missing transverse momentum resolution are shown in this presentation. All studies are done using the recently reconstructed 2017 "Legacy" data. Previous and latest PUPPI tune are compared using the same data. The label "PUPPI v11a" represents the configuration used in Ref [1], the label "PUPPI v15" represents the new configuration.