163 research outputs found
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- interactions, and used to
predict results in low- 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 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. 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 GeV or GeV, which has a precision of , 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 -boson at a photon-photon collider
The top-pair production in association with a -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 in different polarized
photon collision modes. The LO, SM NLO and SQCD NLO corrected distributions of
the invariant mass of -pair and the transverse momenta of final
-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
when goes up from to .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 boson mass measurements from Tevatron experiments
(CDF and D0) in collisions at GeV are reported,
using and data collected at CDF and D0,
respectively. The measurements of boson properties at LHC experiments
(ATLAS, CMS, and LHCb) in collisions at TeV, using data
collected before Summer 2011, are presented. These measurements are essential
at the preparation stage of the boson mass measurements at LHC. Challenges
for mass measurement at the LHC in comparison with the Tevatron are
outlined. Prospects for 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
- …