Related papers: Four quark processes at LEP 200
We study the density of states method to explore the phase diagram of the chiral transition on the tempeature and quark chemical potential plane. Four quark flavours are used in the analysis. Though the method is quite expensive small…
We review here the measurements of W-pair production and W decay rates performed by the four LEP experiments at ECM from 161 to 209 GeV, and their relevance in support of the standard electroweak model.
I review the recent results in the field of QCD at high energy presented to this Conference. In particular, I will concentrate on measurements of $\as$ from studies of event structures and jet rates, jet production in hadronic collisions,…
The \textit{ab initio} approach is used to evaluate the excitation energies of the $2s2p \, ^{2S+1}P_J$ states from the ground state as well as the $2s2p \, ^3P_1 \rightarrow 2s2p \, ^3P_0$ and $2s2p \, ^3P_2 \rightarrow 2s2p \, ^3P_1$…
We review the current status of perturbative corrections in QCD at four loops for scattering processes with space- and time-like kinematics at colliders, with specific focus on deep-inelastic scattering and electron-positron annihilation.…
Electroweak one-loop calculations for production of top-quark pairs at colliders are completed by providing the missing QED type contributions from real and virtual photons, where also effects from interference between QED and QCD…
In this talk we present the current status of the theoretical description of the production of top-quark pairs at the LHC, detailing recent progress for predictions at the stable-top level as well as for predictions that include the decay…
Top-quark pair production with an additional jet is an important signal and background process at the LHC. We present the next-to-leading order QCD calculation for this process and show results for integrated as well as differential cross…
The status of predictions for fermion-pair production at LEP is summarized with emphasis on LEP2 energies and on the physics interest there. Some numerical comparisons with other programs are performed. We also present first results of a…
Data from electron positron annihilations at different center of mass energies are collected by the four LEP experiments. Direct tests of hard QCD are performed by measuring and analysing event shape observables.
We study electron-positron annihilations into six jets at the parton level in perturbative Quantum Chromo-Dynamics (QCD), via the elementary processes $e^+e^-\ar q\bar q gggg$, $e^+e^-\ar q\bar q q'\bar q' gg$ and $e^+e^-\ar q\bar q q'\bar…
We present the results of a lattice calculation of four-quark states with the quark contents $\bar{b}\bar{c}q_1q_2$ where $q_1,q_2 \in u,d,s$. For the spin 1 states, when the light quark ($q_1, q_2$) masses are lighter, we find at least one…
The effects induced by the quark masses in three-jet observables have been studied in this thesis. In particular, we have explored a new method: the study of three-jet observables at LEP, different from QCD Sum Rules and Lattice…
The cross sections for the reaction $\gamma\gamma\rightarrow 4\ell$ in proton--proton collisions are calculated at the LHC energies. We show that the purely electroweak process $\gamma\gamma\rightarrow 4\ell$ can be studied at the LHC and…
Data from LEP2 on hadron production in gamma gamma interactions at high pT exceed the predictions of QCD by about an order of magnitude. The amplitude for the process is asymptotically proportional to the sum of the squares of the charges…
Hadron production in leading order pQCD is reviewed. The shape of the single inclusive particle spectra is well described for $p_T \geq 2-3$ GeV at center of mass energies from 20 GeV to 2 TeV. The phenomenological K-factor is found to…
The quarkonium plus photon production in coherent hadron-hadron interactions at the LHC is studied using the non-relativistic QCD factorization formalism. We investigate a set of kinematic distributions and compute the total cross sections…
We consider forward inclusive production of several quarks in the high energy p-A collisions in the CGC formalism. For three particle production we provide a complete expression in terms of multipole scattering amplitudes on the nucleus and…
I review recent theoretical progress on the description of heavy quark, jet and gauge boson production at colliders within perturbative QCD. Particular emphasis is put on the improved understanding of fragmentation phenomena, resummation of…
The cross-section for the production of $b{\bar b} c{\bar c}$ quarks in $e^+e^-$ annihilation, that proves to be at a level of $\sigma (e^+e^- \rightarrow b{\bar b} c{\bar c})/ \sigma (e^+e^- \rightarrow b{\bar b}) \sim 10^{-2}$ for ${\sqrt…