No Arabic abstract
We present results from CDF and DO on $Wgamma$ and $Zgamma$ productions in $pbar{p}$ collisions at $sqrt{s}=1.8~{rm TeV}.$ The goal of the analyses is to test the non-abelian self-couplings of the $W$, $Z$ and photon, one of the most direct consequences of the $SU(2)_Lotimes U(1)_Y$ gauge symmetry. We present direct measurements of $WWgamma$ couplings and limits on $ZZgamma$ and $Zgammagamma$ couplings, based on $pbar{p}rightarrow ell ugamma + X$ and $pbar{p}rightarrow ellellgamma+X$ events, respectively, observed during the 1992--1993 run of the Fermilab Tevatron Collider.
We consider the production of Wgamma and Zgamma pairs at the LHC, and report on the fully differential computation of next-to-next-to-leading order (NNLO) corrections in QCD perturbation theory. The calculation includes leptonic vector-boson decays with the corresponding spin correlations, off-shell effects and final-state photon radiation. We present numerical results for pp collisions at 7 TeV, and compare them with available ATLAS data. In the case of Zgamma production, the impact of NNLO corrections is generally moderate, ranging from 8% to 17%, depending on the applied cuts. In the case of Wgamma production, the NNLO effects are more important, and range from 19% to 26%, thereby improving the agreement of the theoretical predictions with the data. As expected, a veto against jets significantly reduces the impact of QCD radiative corrections.
We present the latest results on the production of WW, WZ, Wgamma, Zgamma and ZZ events at the Fermilab Tevatron Collider. The results are based on the analyses of 0.2 -- 2 /fb of data collected in p pbar collisions at sqrt(s) = 1.96 TeV by CDF and DO experiments during the Tevatron Run II. Analyses of the diboson production processes provide crucial test of the Standard Model, directly probing its predictions on the Trilinear Gauge Couplings.
A long time ago, at a laboratory far, far away, the Fermilab Tevatron collided protons and antiprotons at $sqrt{s} = 1.96$ TeV. The CDF and D0 experiments each recorded datasets of about 10 fb$^{-1}$. As such experiments may never be repeated, these are unique datasets that allow for unique measurements. This presentation describes recent results from the two experiments on top-quark production rates, spin orientations, and production asymmetries, which are all probes of the $pbar{p}$ initial state.
This paper provides a review of the experimental studies of processes with a single top quark at the Tevatron proton-antiproton collider and the LHC proton-proton collider. Single top-quark production in the t-channel process has been measured at both colliders. The s-channel process has been observed at the Tevatron, and its rate has been also measured at the center-of-mass energy of 8 TeV at the LHC in spite of the comparatively harsher background contamination. LHC data also brought the observation of the associated production of a single top quark with a W boson as well as with a Z boson. The Cabibbo-Kobayashi-Maskawa matrix element |Vtb| is extracted from the single-top-quark production cross sections, and t-channel events are used to measure several properties of the top quark and set constraints on models of physics beyond the Standard Model. Rare final states with a single top quark are searched for, as enhancements in their production rates, if observed, would be clear signs of new physics.
The CDF and D0 collaborations performed a comprehensive study of the production of vector bosons, W and Z, in association with energetic jets. Understanding the W/Z + jets and W/Z + c, b-jets processes is of paramount importance for the top quark physics, for the Higgs boson measurements, and for many new physics searches. In this contribution the most recent measurements of the associated production of jets and vector bosons in Run II at the Tevatron are presented. The measurements are compared to different perturbative QCD predictions and to several Monte Carlo generators.