Measurement of the c-jet mistagging efficiency in t ¯t events using pp collision data at √ s = 13 TeV collected with the ATLAS detector Aad, G. Aguilar Saavedra, Juan Antonio Rodríguez Chala, Mikael A technique is presented to measure the efficiency with which c-jets are mistagged as b-jets (mistagging efficiency) using t ¯t events, where one of theW bosons decays into an electron or muon and a neutrino and the other decays into a quark–antiquark pair. The measurement utilises the relatively large and known W → cs branching ratio, which allows ameasurement to be made in an inclusive c-jet sample. The data sample used was collected by the ATLAS detector at √ s = 13 TeV and corresponds to an integrated luminosity of 139 fb−1. Events are reconstructed using a kinematic likelihood technique which selects the mapping between jets and t ¯t decay products that yields the highest likelihood value. The distribution of the b-tagging discriminant for jets from the hadronic W decays in data is compared with that in simulation to extract the mistagging efficiency as a function of jet transverse momentum. The total uncertainties are in the range 3–17%. The measurements generally agree with those in simulation but there are some differences in the region corresponding to the most stringent b-jet tagging requirement 2023-05-22T08:13:47Z 2023-05-22T08:13:47Z 2023-01-31 journal article Aad, G., Abbott, B., Abbott, D.C. et al. Measurement of the c-jet mistagging efficiency in tt¯ events using pp collision data at s√=13 TeV collected with the ATLAS detector. Eur. Phys. J. C 82, 95 (2022). [https://doi.org/10.1140/epjc/s10052-021-09843-w] https://hdl.handle.net/10481/81692 doi.org/10.1140/epjc/s10052-021-09843-w eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional Springer Nature