Performance and Calibration of the JetFitterCharm Algorithm for c-Jet Identification

An impact parameter and secondary-vertex based charm tagging algorithm, JetFitterCharm, has been developed to distinguish $c$-quark jets from either $b$-quark or light-flavoured ($u$,$d$,$s$-quark or gluon) jets. JetFitterCharm is the first such algorithm used in ATLAS physics searches. This note presents both the expected performance in simulation and results from calibrating the tagging efficiencies of $b$-quark, $c$-quark and light-flavoured jets with data. The calibrations are presented in the form of scale factors, corresponding to the ratios of the tagging efficiencies measured in data to those in simulation. Both simulation and data are based on $\sqrt{s} = 8$ TeV $pp$ collisions.