Related papers: Extraction of alpha_s from the energy evolution of…
The QCD coupling alpha_s is determined at NLO*+NMLLA accuracy from the comparison of experimental jet data to theoretical predictions of the energy-evolution of the parton-to-hadron fragmentation function moments (multiplicity, peak, width,…
The QCD coupling $\alpha_s$ is extracted from the energy evolution of the first two moments (multiplicity and mean) of the parton-to-hadron fragmentation functions at low fractional hadron momentum $z$. Comparisons of the experimental…
The QCD coupling alpha_s is determined from a combined analysis of experimental e+e- and e-p jet data confronted to theoretical predictions of the energy evolution of the parton-to-hadron fragmentation functions (FFs) moments…
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…
The latest experimental and theoretical developments in the high-precision determination of the strong coupling $\alpha_s$ are briefly reviewed. Six groups of observables: (i) lattice QCD data, (ii) hadronic $\tau$ decays, (iii)…
The current world-average of the strong coupling at the Z pole mass, $\alpha_s(m^2_{Z}) = 0.1181 \pm 0.0013$, is obtained from a comparison of perturbative QCD calculations computed, at least, at next-to-next-to-leading-order accuracy, to a…
We present a strong coupling constant extraction at Next-to-Leading Order QCD accuracy using ATLAS Z+2,3,4 jets data. This is the first extraction using processes with a dependency to high powers of the coupling constant. We obtain values…
We have studied hadronic events from e+e- annihilation data at centre-of-mass energies from 91 to 209 GeV. We present distributions of event shape observables and their moments at each energy and compare with QCD Monte Carlo models. From…
Calculations using the AdS/CFT correspondence can be used to unveil the short-distance structure of a strongly coupled plasma, as it would be seen by a `hard probe'. The results of these calculations admit a natural physical interpretation…
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 moments of event shape distributions and the four-jet rate as a function of the Durham…
Recent determinations of alphas(Mz) from the H1 and ZEUS Collaborations using inclusive-jet cross-section measurements in neutral current deep inelastic scattering at high Q2 are presented. A combined value of alphas(mz)=0.1198 +- 0.0019…
We have computed the four lowest even-N moments of all four splitting functions for the evolution of flavour-singlet parton densities of hadrons at the fourth order in the strong coupling constant alpha_s. The perturbative expansion of…
The precision measurements of the strong coupling constant, alphas, and its energy-scale dependence carried out at HERA by the H1 and ZEUS Collaborations are reviewed. An average value of alphas(Mz) = 0.1186 +- 0.0011 (exp.) +- 0.0050 (th.)…
Hadron colliders offer a unique opportunity to test perturbative QCD because, rather than producing events at a specific beam energy, the dynamics of the hard scattering is probed simultaneously at a wide range of momentum transfers. This…
The ZEUS inclusive differential cross-section data from HERA, for charged and neutral current processes taken with e+ and e- beams, together with differential cross-section data on inclusive jet production in e+ p scattering and dijet…
We employ data taken by the JADE and OPAL experiments for an integrated QCD study in hadronic e+e- annihilations at c.m.s. energies ranging from 35 GeV through 189 GeV. The study is based on jet-multiplicity related observables. The…
In this contribution we explore one of the many possibilities of determining the strong coupling constant $\alpha_S$ at hadron colliders. The method considered is quite unique compared to other methods in that the value of $\alpha_S$ is…
We study the global analysis for parton distributions as a function of the QCD strong coupling strength alpha_s, and present a new series of distributions that span the range 0.110 < alpha_s(m_Z) < 0.128. We use these distributions to…
The status of determinations of the QCD coupling constant, alphas, at HERA is reviewed. Since jet final states provide the most relevant input to the HERA determinations of alphas, the relevant methods used in and results from jet physics…
Data from e+e- annihilation into hadrons collected by the JADE experiment at centre-of-mass energies between 14 and 44 GeV were used to study the 4-jet rate using the Durham algorithm as well as the first five moments of event shape…