Performance summary of AK4 jet charm tagging with the CMS Run2 Legacy dataset

Identification of charm (c) jets, i.e. jets originating from c quarks, is an essential ingredient of many measurements as well as searches for new physics beyond the standard model at the LHC. In this Detector Performance Summary, the performance of these algorithms is presented for anti-$k_{T}$ jets with radius parameter 0.4 based on Legacy reconstruction of proton-proton collision data recorded by the CMS experiment at 13 TeV between 2016 and 2018 and compared with expectations based on simulation. Calibration scale factors, accounting for the difference in c jet identification performance between data and simulation, are evaluated with two different approaches. The first approach involves adjusting tagging and mistagging efficiencies at fixed working points, while the second involves adjusting the entire distributions of the outputs of the tagging algorithm. Results from both the approaches are reported in this summary.