A technique is presented to measure the efficiency with which c-jets are mistagged as b-jets (mistagging efficiency) using t tbar events, where one of the W 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 → c s branching ratio, which allows a measurement to be made in an inclusive c-jet sample. The data sample used was collected by the ATLAS detector at sqrt(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 tbar 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.

Measurement of the c-jet mistagging efficiency in tt¯ events using pp collision data at √s=13 TeV collected with the ATLAS detector

Agarwala J.;Farina E. M.;Introzzi G.;Livan M.;Negri A.;Pezzotti L.;Rebuzzi D. M.;Rimoldi A.;Rovelli G.;Sottocornola S.;
2022-01-01

Abstract

A technique is presented to measure the efficiency with which c-jets are mistagged as b-jets (mistagging efficiency) using t tbar events, where one of the W 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 → c s branching ratio, which allows a measurement to be made in an inclusive c-jet sample. The data sample used was collected by the ATLAS detector at sqrt(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 tbar 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.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/1474157
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