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Related papers: Review of alpha_s determinations

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Determinations of alpha_s are reviewed. Current results are limited to a precision of around 3-20%, largely by theoretical uncertainties. All measurements are consistent with a `world average' value of 0.118 +- 0.005 and there is no…

High Energy Physics - Experiment · Physics 2011-07-19 P. N. Burrows

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.)…

High Energy Physics - Experiment · Physics 2015-06-25 Claudia Glasman

The theory of strong interactions, QCD, is described in terms of a few parameters, namely the strong coupling constant alpha_s and the quark masses. We show how these parameters can be determined reliably using computer simulations of QCD…

Computational Physics · Physics 2007-05-23 Rainer Sommer , Hartmut Wittig

A QCD model with an infinite number of vector mesons suggested by one of the authors is used to derive the value of the correction $\delta\alpha_{hadr}$ for $\alpha(m_{Z}^{2})$ due to the strong interactions. The result is…

High Energy Physics - Phenomenology · Physics 2009-10-28 B. V. Geshkenbein , V. L. Morgunov

A vast program of determinations of the strong coupling $\alpha_\mathrm{S}$ is being undertaken by CMS. These measurements exploit several QCD-dominated processes that are sensitive to $\alpha_\mathrm{S}$, and present different theoretical…

High Energy Physics - Experiment · Physics 2024-09-25 Patrick L. S. Connor

The strong coupling alpha_s(M_Z^2) has been measured using hadronic decays of Z^0 bosons collected by the SLD experiment at SLAC. The data were compared with QCD predictions both at fixed order, O(alpha_s^2), and including resummed analytic…

High Energy Physics - Experiment · Physics 2008-11-26 K. Abe

The asymptotical behaviour of the QCD coupling strength is considered. Its upper bound is found from the present experimental data. The assumption about the finite asymptotical value of the coupling strength leads to the energy scale where…

High Energy Physics - Phenomenology · Physics 2007-05-23 I. M. Dremin

In this lecture, after recalling the basic definitions and facts about the running coupling in QCD, I present a critical discussion of the methods for measuring $\alpha_s$ and select those that appear to me as the most reliably precise

High Energy Physics - Phenomenology · Physics 2013-03-26 Guido Altarelli

We present a new determination of the strong coupling constant $\alpha_s$ from a global QCD analysis CT25 of parton distribution functions (PDFs) that incorporates high-precision experimental measurements from the Run-2 of the Large Hadron…

High Energy Physics - Phenomenology · Physics 2026-03-18 Alim Ablat , Sayipjamal Dulat , Marco Guzzi , Joey Huston , Kirtimaan Mohan , Pavel Nadolsky , Dan Stump , C. -P. Yuan

Theoretical predictions for particle production cross sections and decays at colliders rely heavily on perturbative Quantum Chromodynamics (QCD) calculations, expressed as an expansion in powers of the strong coupling constant $\alpha_s$.…

We discuss the determination of the strong coupling $\alpha_\mathrm{\overline{MS}}^{}(m_\mathrm{Z})$ or equivalently the QCD $\Lambda$-parameter. Its determination requires the use of perturbation theory in $\alpha_s(\mu)$ in some scheme,…

High Energy Physics - Phenomenology · Physics 2016-11-02 Mattia Dalla Brida , Patrick Fritzsch , Tomasz Korzec , Alberto Ramos , Stefan Sint , Rainer Sommer

The `XIIIth Quark Confinement and the Hadron Spectrum' conference (Confinement 2018) contained a `Round Table Discussion' on the status of the determinations of the strong coupling $\alpha_s(m_Z)$ as well as prospects for future…

High Energy Physics - Phenomenology · Physics 2018-12-17 Antonio Pich , Juan Rojo , Rainer Sommer , Antonio Vairo

We determine the value of the strong coupling $\alpha_\text{s}$ and study its running over a wide range of scales as probed by the dijet production process at hadron colliders, based on an NNLO QCD analysis of LHC dijet data. From a large…

The four-loop determination of the strong coupling from fully inclusive observables is reviewed. Special attention is given to the low-energy measurement extracted from the hadronic $\tau$ decay width. A recent exhaustive analysis of the…

High Energy Physics - Phenomenology · Physics 2017-04-05 Antonio Pich

We present an overview of the recent lattice determination of the QCD coupling $\alpha_s$ by the ALPHA Collaboration. The computation is based on the non-perturbative determination of the $\Lambda$-parameter of $N_{\rm f}=3$ QCD, and the…

High Energy Physics - Phenomenology · Physics 2018-12-18 Mattia Dalla Brida

The current phenomenological determinations of $\alpha_s(M_\tau)$ and $\alpha_s(M_Z)$ are shown to be only marginally consistent with the QCD evolution of the strong coupling constant between $M_Z$ and $M_\tau$. This motivates a revised…

High Energy Physics - Phenomenology · Physics 2007-05-23 T. G. Steele , V. Elias

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…

High Energy Physics - Experiment · Physics 2008-11-26 The Jade , the OPAL collaborations , P. Pfeifenschneider

We give a brief review of our recent QCD analysis carried out over the deep inelastic scattering data on F2 structure function and in the non-singlet approximation to the accuracy up to next-to-next-to-leading-order. Specifically, analysis…

High Energy Physics - Phenomenology · Physics 2010-08-05 A. V. Kotikov , V. G. Krivokhizhin , B. G. Shaikhatdenov , G. Parente

The magnitude of the strong interaction is characterized by $\alpha_s$, the coupling parameter in Quantum Chromodynamics (QCD), a parameter with an unexplained value in the Standard Model. In this paper, a candidate explanation for…

High Energy Physics - Phenomenology · Physics 2010-08-03 David Batchelor

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…

High Energy Physics - Experiment · Physics 2007-05-23 P. A. Movilla Fernandez