Related papers: Four quark processes at LEP 200
This report summarises the results of the four-fermion working group of the LEP2-MC workshop, held at CERN from 1999 to 2000. Recent developments in the calculation of four-fermion processes in electron-positron collisions at LEP-2…
We calculate \alpha^{2}\alpha_{s}^{2} order QED contribution to J/\psi production in pp(\bar{p})\to J/\psi+c\bar{c} color-singlet process at the Tevatron and LHC in the framework of non-relativistic QCD. The contribution of the interference…
One loop QCD corrections to hadronic W decay are calculated for arbitrary W polarizations . The results are applied to W pair production and decay at LEP200. We focus on the corrections to angular distributions with particular emphasis on…
In this talk, I briefly review several models of the heavy quarkonium production at collider energies, and discuss the status of QCD factorization for these production models.
Effects of four-Fermi-type new interactions are studied in top-quark pair production and their subsequent decays at future e^+e^- colliders. Secondary-lepton-energy distributions are calculated for arbitrary longitudinal beam polarizations.…
Next-to-leading order calculation for three jet heavy quark production in e^+e^- collisions, including complete quark mass effects, is reviewed. Its applications at LEP/SLC are also discussed.
We compute the order-$\as$ corrections to the total cross section and to jet rates for the process $\epem\to\epem +$ hadrons, where the hadrons are produced through crossed-channel quark exchange in the hard scattering of two off-shell…
Theoretical predictions for the production cross sections of leptoquarks at the CERN LHC are presented including higher-order QCD corrections. These corrections reduce the dependence on the renormalization/factorization scales…
Many theories, from Supersymmetry to models of Strong Electroweak Symmetry Breaking, look at the production of four top quarks as an interesting channel to evidentiate signals of new physics beyond the Standard Model. The production of…
Evidence for the production of exotic hadron states composed of five quarks (pentaquarks) has been searched for in data collected by the ALEPH, DELPHI, and L3 experiments at LEP. No significant signal is observed. Several 95% C.L. upper…
QCD one-loop corrections to the full gauge invariant set of electroweak diagrams describing the hadronic process $e^+ e^- \to u~\bar d~s~\bar c$ are computed. Four-jet shape variables for $WW$ events are studied at next-to-leading order and…
In the events of the type $e^+e^- \rightarrow W^+W^- \rightarrow$ 4 jets, $e^+e^- \rightarrow t\bar{t} \rightarrow bW^+\bar{b}W^-$, particle production could depend in a non-trivial way on the kinematics of the process. It is shown that QCD…
The present knowledge on four-fermion production in electron-positron collisions is reviewed, with emphasis on W boson physics. Different methods to extract M_W from the data are presented and the role of QCD loop corrections discussed.
A brief summary is given of some recent perturbative QCD results on the evaluation of cross sections and on the the structure of final states in processes with incoming hadrons at small $x$. A new Monte Carlo simulation which includes these…
Four-fermion production via electroweak neutral currents has been measured by all four LEP collaborations at center-of-mass energies near the Z resonance and for the first time also at energies well above the Z peak. Essentially all…
This paper studies the electroweak production of all possible four fermion states in e+ e- collisions. Since the methods employed to evaluate the complete matrix elements and phase space are very general, all four fermion final states in…
The measurements of four-fermion production rates performed at LEP2 in e+e- collisions at centre-of-mass energies ranging from 161 to 209 GeV are presented. The focus is put on processes that involve the production and decay of W or Z…
An overview of recent results from LEP concerning the hadronisation process is presented. Emphasis is placed on the $b$-quark. The first presented analysis is the measurement of the $b$-quark fragmentation function. It includes a new,…
We analyze light meson electroproduction in the intermediate energy range where the quark contributions are essential. Our calculations are carried out on the basis of the handbag approach. We study cross sections and spin asymmetries for…
We discuss the results for the four-top quark production process at the LHC at NLO accuracy in perturbative QCD for the $3\ell$ decay channel. The QCD corrections are applied in both the production and the decay stages of the four top…