Measurement of t-channel single top-quark production with the ATLAS detector

The electroweak production of singly produced top quarks at the LHC operating at a center of mass energy of sqrt(s) = 7 TeV is dominated by the t-channel exchange of a virtual W boson that is emitted by a light quark inside one of the colliding protons. Thus, the measurement of the top-quark and top-antiquark production cross sections is sensitive to the u-quark PDF and the d-quark PDF for a momentum fraction x of the incoming light quarks and can provide complementary input to constrain these PDF in the range of 0.02 < x < 0.5. Furthermore, the cross section is proportional to the square of the CKM matrix element |Vtb| and the measurement can thus provide additional input to constrain the quark mixing matrix without assumptions on the number of quark generations.