Related papers: Four quark processes at LEP 200

The production of charm and beauty quarks in $\gamma \gamma$ collisions at LEP, $ep$ collisions at HERA and $p \bar{p}$ collisions at the Tevatron is discussed. The comparison with predictions of next-to-leading-order QCD and the issues it…

The calibration QED process cross sections for experiments on planned electron-photon and photon-photon colliders for detecting the small angles scattered particles are calculated. These processes describe the creation of two jets moving…

This thesis can be divided into several parts. The first one consists in a detailed historical review of quarkonium physics, centered on the different production models successively introduced. Then comes a review of the currently available…

We calculate four-loop QCD corrections to the electroweak $\rho$ parameter with a non-vanishing $b$ quark mass. At three loops, it was observed that elliptic integrals contribute to this observable. This prompts the question of which…

A search for a first generation scalar leptoquark (LQ) has been performed using the data collected by the OPAL detector in 1996 at e+e- centre-of-mass energies sqrt{s} of 161 and 172 GeV. It is assumed that a single leptoquark can be…

In certain regions of phase space in jet production, large logarithms can arise which are resummed by the BFKL equation. Linear colliders can potentially be excellent places to study BFKL effects in jet production. We discuss an approach to…

Inclusive charged hadron production, e+e- -> e+e- h+- X, is studied using 414 pb-1 of data collected at LEP with the L3 detector at centre-of-mass energies between 189 and 202 GeV. Single particle inclusive differential cross sections are…

We investigate the rapidity and transverse momentum distributions of the prompt photon production at the CERN LHC energies considering the current perturbative QCD approaches for this scattering process. Namely, we compare the predictions…

The double coherent and non-coherent diffractive production of heavy quark - antiquark pairs ($Q \bar{Q}$) in heavy ion scattering at high energies (LHC) is considered. The total and differential cross sections of these processes with the…

We present the cross sections for production of up to four jets at the Large Hadron Collider, at next-to-leading order in the QCD coupling. We use the BlackHat library in conjunction with SHERPA and a recently developed algorithm for…

We consider top-antitop quark ($t{\bar t}$) production at the Large Hadron Collider (LHC) with subsequent decay into dileptonic and lepton plus jets final states. We present a set of leptonic angular correlations and distributions with…

This contribution -- a continuation of earlier work -- reports on recent developments in the calculation and understanding of 4-quark energies generated using lattice Monte Carlo techniques.

We present updated predictions for the total cross section of top-quark pair production at Tevatron and LHC. For the LHC we also provide results at sqrt(s) = 10 TeV, in view of the anticipated run in 2008 and quote numbers for the…

Studies of hadronic final states of $e^+e^-$ annihilations, observed at the Large Electron Positron Collider LEP at CERN, are reviewed. The topics included cover measurements of $\alpha_s$, hadronic event shapes and hadronisation studies,…

We calculate the next-to-leading order (NLO) quantum chromodynamics (QCD) corrections to double charmonium production processes $e^+e^-\to\gamma^*\to\eta_c+h_c(1P)/\psi_{1,2}(1D)$ within the non-relativistic QCD (NRQCD) factorization…

The measurements of the QED reaction $ \EEGG $ performed with the L3 detector are used to search for new physics phenomena beyond the Standard Model. No evidence for these phenomena is found and new limits on their parameters are set. First…

This report summarizes the results of the two-fermion working group of the LEP2-MC workshop, held at CERN from 1999 to 2000. Recent developments in the theoretical calculations of the two fermion production process in the electron-positron…

Precise predictions for an $e^+e^-\rightarrow t\bar{t}$ cross-section are presented in the energy region from 400 GeV to 800 GeV. Cross-sections are estimated including the beam-polarization effects with full $\mathcal{O}(\alpha)$, and also…

Heavy quark productions in high energy polarized scatterings are reviewed from a personal point of view. After mentioning why heavy quark physics is so interesting, I concentrate on two rather specific subjects: (1) polarized…

Compact lattice Quantum Electrodynamics (QED) with four species of fermions is simulated with massless quarks by using the $\chi$QED scheme of adding a four-fermi interaction to the action. Simulations directly in the chiral limit of…