Top, W and Z: Experimental results

In this paper we will review the most recent experimental results obtained at Tevatron (Fermilab) on top and electroweak physics

Precision Electroweak Measurements and Constraints on the Standard Model

This note presents constraints on Standard Model parameters using published and preliminary precision electroweak results measured at the electron-positron colliders LEP and SLC. The results are compared with precise electroweak measurements from other experiments, notably CDF and D{\O}at the Tevatron. Constraints on the input parameters of the Standard Model are derived from the combined set of results obtained in high-$Q^2$ interactions, and used to predict results in low-$Q^2$ experiments, such as atomic parity violation, M{\o}ller scattering, and neutrino-nucleon scattering. The main changes with respect to the experimental results presented in 2008 are new combinations of results on the W-boson mass and the mass of the top quark.Comment: 18 page

Combination of the top-quark mass measurements from the Tevatron collider

The top quark is the heaviest known elementary particle, with a mass about 40 times larger than the mass of its isospin partner, the bottom quark. It decays almost 100% of the time to a $W$ boson and a bottom quark. Using top-antitop pairs at the Tevatron proton-antiproton collider, the CDF and {\dzero} collaborations have measured the top quark's mass in different final states for integrated luminosities of up to 5.8 fb$^{-1}$. This paper reports on a combination of these measurements that results in a more precise value of the mass than any individual decay channel can provide. It describes the treatment of the systematic uncertainties and their correlations. The mass value determined is $173.18 \pm 0.56 \thinspace ({\rm stat}) \pm 0.75 \thinspace ({\rm syst})$ GeV or $173.18 \pm 0.94$ GeV, which has a precision of $\pm 0.54$, making this the most precise determination of the top quark mass.Comment: 30 pages and 6 figures, published in Phys. Rev.

SUSY QCD impact on top-pair production associated with a Z0Z^0-boson at a photon-photon collider

The top-pair production in association with a $Z^0$-boson at a photon-photon collider is an important process in probing the coupling between top-quarks and vector boson and discovering the signature of possible new physics. We describe the impact of the complete supersymmetric QCD(SQCD) next-to-leading order(NLO) radiative corrections on this process at a polarized or unpolarized photon collider, and make a comparison between the effects of the SQCD and the standard model(SM) QCD. We investigate the dependence of the lowest-order(LO) and QCD NLO corrected cross sections in both the SM and minimal supersymmetric standard model(MSSM) on colliding energy $\sqrt{s}$ in different polarized photon collision modes. The LO, SM NLO and SQCD NLO corrected distributions of the invariant mass of $t\bar t$-pair and the transverse momenta of final $Z^0$-boson are presented. Our numerical results show that the pure SQCD effects in \ggttz process can be more significant in the $+ +$ polarized photon collision mode than in other collision modes, and the relative SQCD radiative correction in unpolarized photon collision mode varies from 32.09% to $-1.89$ when $\sqrt{s}$ goes up from $500 GeV$ to $1.5 TeV$.Comment: 22 pages and 13 figure

2012 Update of the Combination of CDF and D0 Results for the Mass of the W Boson

We summarize and combine the results on the direct measurements of the mass of the W boson in data collected by the Tevatron experiments CDF and D0 at Fermilab. Earlier results from CDF Run-0 (1988--1989), D0 and CDF Run-I (1992--1995) and D0 results from 1/fb (2002--2006) of Run-II data are now combined with two new, high statistics Run-II measurements: a CDF measurement in both electron and muon channels using 2.2/fb of integrated luminosity collected between 2002 and 2007, and a D0 measurement in the electron channel using 4.3/fb collected between 2006 and 2009. As in previous combinations, the results are corrected for inconsistencies in parton distribution functions and assumptions about electroweak parameters used in the different analyses. The resulting Tevatron average for the mass of the W boson is Mw = 80387 +- 16 MeV and a new world average including data from LEP II is Mw = 80385+- 15 MeV.Comment: 11 pages, 1 figur

W Mass results from Tevatron and LHC

Most recent results of $W$ boson mass measurements from Tevatron experiments (CDF and D0) in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ GeV are reported, using $0.2 fb^{-1}$ and $1.0 fb^{-1}$ data collected at CDF and D0, respectively. The measurements of $W$ boson properties at LHC experiments (ATLAS, CMS, and LHCb) in $pp$ collisions at $\sqrt{s}=7$ TeV, using data collected before Summer 2011, are presented. These measurements are essential at the preparation stage of the $W$ boson mass measurements at LHC. Challenges for $W$ mass measurement at the LHC in comparison with the Tevatron are outlined. Prospects for $W$ mass precision with upcoming measurements and its implications are discussed.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 4 pages, 13 figure

Vector boson production at hadron colliders: a fully exclusive QCD calculation at NNLO

We consider QCD radiative corrections to the production of W and Z bosons in hadron collisions. We present a fully exclusive calculation up to next-to-next-to-leading order (NNLO) in QCD perturbation theory. To perform this NNLO computation, we use a recently proposed version of the subtraction formalism. The calculation includes the gamma-Z interference, finite-width effects, the leptonic decay of the vector bosons and the corresponding spin correlations. Our calculation is implemented in a parton level Monte Carlo program. The program allows the user to apply arbitrary kinematical cuts on the final-state leptons and the associated jet activity, and to compute the corresponding distributions in the form of bin histograms. We show selected numerical results at the Tevatron and the LHC.Comment: 7 pages, 3 ps figure