Prof. Christian Schwanenberger (University of Manchester)
We present measurements of the cross sections for the two main production modes of single top quarks in pp(bar) collisions at a center-of-mass energy of 1.96 TeV in the Run II data collected with the D0 detector at the Fermilab Tevatron Collider. For this measurement the full D0 data set corresponding to an integrated luminosity of 9.7 fb−1 is used. We present the evidence of the s-channel production with a significance of 3.7 standard deviations. We also present an updated measurement of the production cross section of t- and s+t-channels. Using these measurements we set a lower limit on the CKM matrix element |Vtb| > 0.92 at 95% C.L., assuming m(top) = 172.5 GeV. We also report the first observation of single top quark production in the s-channel through the combination of the CDF and D0 measurements with a significance of 6.3 standard deviations.
et al. D0 Collaboration (Fermi National Accelerator Laboratory)