Measurement of the single top quark and antiquark production cross sections in the $t$ channel and their ratio in proton-proton collisions at $\sqrt{s} = $ 13 TeV

Abstract Measurements of the cross sections for the production of single top quarks and antiquarks in the t channel, and their ratio, are presented for proton-proton collisions at a center-of-mass energy of 13 TeV. The data set used was recorded in 2016 by the CMS detector at the LHC and corresponds to an integrated luminosity of 35.9 fb−1. Events with one muon or electron are selected, and different categories of jet and b jet multiplicity and multivariate discriminators are applied to separate the signal from the background. The cross sections for the t-channel production of single top quarks and antiquarks are measured to be 130 ± 1 ( stat ) ± 19 ( syst ) pb and 77 ± 1 ( stat ) ± 12 ( syst ) pb , respectively, and their ratio is 1.68 ± 0.02 ( stat ) ± 0.05 ( syst ) . The results are in agreement with the predictions from the standard model.