Related papers: QCD studies in e+e- annihilation from 30GeV to 189…
Single particle inclusive energy spectra in $e^+e^-$ annihilation are analyzed in terms of moments. By assuming Local Parton Hadron Duality (LPHD), experimental data in a wide c.m. energy range from 3 GeV up to LEP energy are compared to…
The moments of the single inclusive momentum distribution of hadrons in QCD jets, are studied in the next-to-modified-leading-log approximation (NMLLA) including next-to-leading-order (NLO) corrections to the alpha_s strong coupling. The…
We present recent results from experimental studies of power corrections in the model of Dokshitzer, Marchesini and Webber using data from the process e+e- -> hadrons at several centre-of-mass energies. Fitted O(alpha_S^2)+NLLA QCD…
The strong coupling constant alpha_S is determined using recently re-analysed e+e- annihilation data collected by the JADE experiment at sqrt{s}= 14 to 44 GeV. The measurements are based on O(alpha_S**2)+NLLA predictions for various event…
Recent improvements in the low energy e+e- annihilation data and their influence on the determination of the hadronic contribution to the running of the QED fine structure constant at m_Z are discussed. Using CMD-2 and KLOE measurements in…
The measurement of the strong coupling alpha_S using hadronic event shape distributions measured with the OPAL detector at center-of-mass energies between 91 and 209 GeV is summarized. For this measurement hadronic event shape distributions…
We report on measurements of e+e- annihilation into hadrons and lepton pairs. The data have been collected with the L3 detector at LEP at centre-of-mass energies between 130 and 189 GeV. Using a total integrated luminosity of 243.7 pb^-1,…
The issue is the expediency of the QCD notions use in the low energy region down to the confinement scale, and, in particular, the efficacy of the QCD invariant coupling \bar{\alpha}_s(Q^2) with a minimal analytic modification in this…
For high energy processes ($M\gg \Lambda_{QCD}$) there are infrared safe hadronic shape variables that have a calculable perturbative expansion in $\alpha_s(M^2)$. However, nonperturbative power suppressed corrections to these variables are…
Data from e+e- annihilation into hadrons collected by the JADE experiment at centre-of-mass energies between 14 GeV and 44 GeV were used to study the four-jet rate as a function of the Durham algorithm's resolution parameter y_cut. The…
e^+e^- annihilation data recorded by the JADE detector at PETRA were used to measure the C-parameter for the first time at sqrt{s}= 35 and 44 GeV. The distributions were compared to a resummed QCD calculation which recently became available…
Predictions of analytical models for hadronisation, namely the dispersive model, the shape function and the single dressed gluon approximation, are compared with moments of hadronic event shape distributions measured in \epem annihilation…
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.
Event shape distributions in $e^+e^-$ annihilation are determined from the DELPHI data taken between 183 and 207\gev. From these the strong coupling $\alpha_s$ is extracted with several techniques. Together with the results from other LEP2…
Infrared and collinear events shapes are suited to directly probe properties of hard QCD. They are traditionally used to measure the strong coupling and to test the gauge structure of QCD. Perturbative predictions exist in several…
A study of event shape observables in proton-antiproton collisions at 1.96 TeV is presented. The data for this analysis were recorded by the CDF II detector at the Tevatron collider. The variables studied are the transverse thrust and…
We reevaluate the hadronic contribution to the running of the QED fine structure constant alpha(s) at s = M_Z^2. We use data from e+e- annihilation and tau decays at low energy and at the qq-bar thresholds, where resonances occur. Using…
Studies of hadronic final states of $e^+e^-$ annihilations at LEP are reviewed. The topics included cover hadronic event shapes, measurements of $\alpha_s$, determinations of QCD colour factors and tests of the non-Abelian gauge structure…
A measurement of event shape variables is presented for large momentum transfer proton-proton collisions using the ATLAS detector at the Large Hadron Collider. Six event shape variables calculated using hadronic jets are studied in…
The measurement of charged-particle event shape variables is presented in inclusive inelastic pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust…