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A new calibration method for charm jet identification validated with proton-proton collision events at $\sqrt{s}$ =13 TeV

The collaboration
CMS-BTV-20-001, 2021.

Abstract
Many measurements at the LHC require efficient identification of heavy-flavour jets, i.e., jets originating from bottom (b) or charm (c) quarks. An overview of the algorithms used to identify c jets is described and a novel method to calibrate them is presented. This new method adjusts the entire distributions of the outputs obtained when the algorithms are applied to jets of different flavours. It is based on an iterative approach exploiting three distinct control regions that are enriched with either b jets, c jets, or light-flavour and gluon jets. Results are presented in the form of correction factors evaluated using proton-proton collision data with an integrated luminosity of 41.5 fb$^{-1}$ at $\sqrt{s}$ = 13 TeV, collected by the CMS experiment in 2017. The closure of the method is tested by applying the measured correction factors on simulated data sets and checking the agreement between the adjusted simulation and collision data. Furthermore, a validation is performed by testing the method on pseudodata, which emulate different miscalibration conditions. The calibrated results enable the use of the full distributions of heavy-flavour identification algorithm outputs, e.g. as inputs to machine-learning models. Thus, they are expected to increase the sensitivity of future physics analyses.

• #### Figure 9 DeepCSV

Data from Figure 9, DeepCSV

10.17182/hepdata.114864.v1/t1

The shape calibration SF values as a function of CvsL and CvsB for DeepCSV-based c taggers for c jets

• #### Figure 10 DeepCSV

Data from Figure 10, DeepCSV

10.17182/hepdata.114864.v1/t2

The shape calibration SF values as a function of CvsL and CvsB for DeepCSV-based c taggers for b jets

• #### Figure 11 DeepCSV

Data from Figure 11, DeepCSV

10.17182/hepdata.114864.v1/t3

The shape calibration SF values as a function of CvsL and CvsB for DeepCSV-based c taggers for light-flavour jets

• #### Figure 9 DeepJet

Data from Figure 9, DeepJet

10.17182/hepdata.114864.v1/t4

The shape calibration SF values as a function of CvsL and CvsB for DeepJet-based c taggers for c jets

• #### Figure 10 DeepJet

Data from Figure 10, DeepJet

10.17182/hepdata.114864.v1/t5

The shape calibration SF values as a function of CvsL and CvsB for DeepJet-based c taggers for b jets

• #### Figure 11 DeepJet

Data from Figure 11, DeepJet

10.17182/hepdata.114864.v1/t6

The shape calibration SF values as a function of CvsL and CvsB for DeepJet-based c taggers for light-flavour jets