Measurement of the t-Channel Single-Top-Quark Production Cross Section and of the |V[subscript tb]| CKM Matrix Element in Pp Collisions at √s = 8 TeV

Abstract

Measurements are presented of the t-channel single-top-quark production cross section in proton-proton collisions at √s = 8 TeV. The results are based on a data sample corresponding to an integrated luminosity of 19.7 fb[superscript −1] recorded with the CMS detector at the LHC. The cross section is measured inclusively, as well as separately for top (t) and antitop ([¯ over t]) , in final states with a muon or an electron. The measured inclusive t-channel cross section is σ [subscript t-ch.] = 83.6 ± 2.3 (stat.) ± 7.4 (syst.) pb. The single t and [¯ over t] cross sections are measured to be σ [subscript t-ch.](t) = 53.8 ± 1.5 (stat.) ± 4.4 (syst.) pb and σ [subscript t-ch.] ([¯ over t]) = 27.6 ± 1.3 (stat.) ± 3.7 (syst.) pb, respectively. The measured ratio of cross sections is R [subscript t-ch.] = σ [subscript t-ch.](t)/σ [subscript t-ch.] ([¯ over t]) = 1.95 ± 0.10 (stat.) ± 0.19 (syst.), in agreement with the standard model prediction. The modulus of the Cabibbo-Kobayashi-Maskawa matrix element V [subscript tb] is extracted and, in combination with a previous CMS result at √s = 7 TeV, a value |V [subscript tb]| = 0.998 ± 0.038 (exp.) ± 0.016 (theo.) is obtained.