Related papers: Four quark processes at LEP 200
The calculation of the tree-level QCD processes e+e- -> qqgggg, qqqqgg and qqqqqq has recently been accomplished. We highlight here the relevance of such reactions for some of the physics at future electron-positron linear accelerators.
Heavy quark production in five jet events at $e^+e^-$ colliders is studied at tree level using helicity amplitudes. Total production rates for $2b3j$ and $4bj$ are given and compared with the corresponding results for massless quarks. The…
We investigate the discovery potential for first generation leptoquarks at the LEP and LEP200 $e^+e^-$ colliders. We consider single leptoquark production via resolved photon contributions which offers a much higher kinematic limit than the…
We present results of phenomenological studies for top-quark pair production at the LHC at the center of mass energy $\sqrt{S} = 7$ TeV. The transverse momentum and rapidity distributions for final-state top quarks are calculated in…
The processes of six-quark production with one $b\bar b$ pair are studied by means of a complete tree-level electroweak calculation. The top-quark signal is examined: the importance of electroweak backgrounds, of the order of 10% above the…
Relativistic configuration-interaction calculations have been performed for the energy levels of the low-lying and core-excited states of beryllium-like argon, Ar$^{14+}$. These calculations include the one-loop QED effects as obtained by…
The theoretical description of heavy quarkonium production at high-energy p-pbar and e-p colliders is reviewed. Predictions based on non-relativistic QCD factorisation are confronted with recent charmonium and bottomonium data from the…
In view of the forthcoming experiments at high energy $e^+ e^-$ colliders, LEP2 and beyond, the process $e^+ e^- \to W^+ W^- \to 4f$ has been investigated for {\it off-shell} $W$'s. After deriving the matrix element for the process within…
A study of the production and the decay of scalar and vector leptoquarks at high-energy e+ e- colliders is presented. All tree-order contributions to single leptoquark production have been calculated and incorporated in the Monte Carlo…
A truncated determinant algorithm is used to study the physical effects of the quark eigenmodes associated with eigenvalues below 400 MeV. This initial study focuses on coarse lattices (with O(a^2) improved gauge action), light internal…
Recent QCD results from ATLAS taken at 7 TeV center-of-mass energy using the LHC are presented, including: dijet production, isolated photon production, isolated photon production associated with jets, jet shapes in top-quark pair events,…
Triggered by the observation of four top-quark production at the LHC by the ATLAS and CMS collaboration we report on the calculation of the next-to-leading order QCD corrections to the Standard Model process $pp \to t\bar{t}t\bar{t}$ in the…
Total hadron multiplicities and multiplicities of hadrons in events with heavy quarks in $e^+e^-$ annihilation at the energies of LEP-1.5 and LEP-2 are calculated on the basis of QCD.
The Odderon state in perturbative QCD is briefly reviewed. Recent calculations devoted to estimate the diffrative eta_c production at high energies from the leading known Odderon states are discussed.
I will attempt to survey some selected physics issues on QCD interconnection phenomena in the processes $e^+e^-\to W^+W^-\to$ 4 jets and $e^+e^-\to t\bar t \to b W^+\bar b W^-$. Possible consequences for LEP2 and future linear $e^+e^-$…
We present a computation of QCD next-to-leading order virtual corrections to the top production and decay process at linear colliders. The top quarks are allowed to be off-shell and the production and decay subprocesses are treated…
We examined the single production of fourth family b' quarks at the Large Hadron electron Collider (LHeC).We have analyzed the background and the signal processes for the mass range 300-800 GeV. We find the discovery region for an optimal…
The production of top-quark pairs that subsequently decay hadronically and leptonically (lepton+jets channel) is one of the key processes for the study of top-quark properties at the LHC. In this article, NLO QCD corrections of order…
We consider quantum electrodynamics (QED) corrections to the fine splitting $E(2P_{3/2}) - E(2P_{1/2})$ in the Li atom. We derive complete formulas for the $m\,\alpha^6$ and $m\,\alpha^7\,\ln\alpha$ contributions and calculate them…
Hadron production and lepton-pair production in e+e- collisions are studied with data collected with the L3 detector at LEP at centre-of-mass energies sqrt{s}=192-208GeV. Using a total integrated luminosity of 453/pb, 36057 hadronic events…