Download or read book The QCD Effective Coupling Constant in E E Annihilation written by A. Ali and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The QCD Effective Coupling Constant in E e Annihilation written by and published by . This book was released on 1981 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The QCD effective coupling constant in e annihilation written by Ahmed Ali and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On the model dependence of the determination of the strong coupling constant in second order QCD form e 1hn e 1hn ee annihilation into hadrons written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An analysis of the charged and neutral energy flow in e hadronic annihilation at 34 GeV and a determination of the QCD effective coupling constant written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Calorimetric Measurement of the Strong Coupling Constant in Electron positron Annihilation at a Center of mass Energy of 91 6 GeV written by and published by . This book was released on 1994 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, a measurement of the strong coupling constant [alpha]{sub s} in ee{sup -} annihilation at a center-of-mass energy of 91.6 GeV is presented. The measurement was performed with the SLD at the Stanford Linear Collider facility located at the Stanford Linear Accelerator Center in California. The procedure used consisted of measuring the rate of hard gluon radiation from the primary quarks in a sample of 9,878 hadronic events. After defining the asymptotic manifestation of partons as `jets`, various phenomenological models were used to correct for the hadronization process. A value for the QCD scale parameter [Lambda]{sub bar MS}, defined in the {sub bar MS} renormalization convention with 5 active quark flavors, was then obtained by a direct fit to O([alpha]{sub s}2) calculations. The value of [alpha]{sub s} obtained was [alpha]{sub s}(M{sub z0}) = 0.122 ± 0.004 {sub -0.007} {sup +0.008} where the uncertainties are experimental (combined statistical and systematic) and theoretical (systematic) respectively. Equivalently, [Lambda]{sub bar MS} = 0.28 {sub -0.10}{sup +0.16} GeV where the experimental and theoretical uncertainties have been combined.

Download or read book On the Model Dependence of the Determination of the Strong Coupling Constant in Second Order QCD from E e annihilation Into Hadrons written by CELLO Collaboration and published by . This book was released on 1983 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comparison of E e Annihilation with QCD and Determination of the Strong Coupling Constant written by TASSO Collaboration and published by . This book was released on 1980 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Results on QCD Quantum Chromodynamics from Ee Annihilation written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A review is given on QCD results from studying ee− annihilation with the PEP and PETRA storage rings with special emphasis on jet physics and the determination of the strong coupling constant .cap alpha./sub s/. 92 refs., 28 figs., 3 tabs.

Download or read book Experimental Determination of an Effective Coupling Constant written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum chromodynamics (QCD), the theory of the strong force, describes the interactions of two basic building blocks of matter: quarks and gluons. High precision data taken at the Jefferson Lab electron accelerator provide a solid basis for the detailed study of many aspects of QCD. The accelerator's beam energy permits investigations of the transition between the short distance and long distance regimes of the strong force. Understanding how the descriptions of these regimes are related is essential in comprehending the structure of ordinary matter. Using new data from polarized electron - nucleon scattering, we extract the scale dependence of an effective strong coupling constant, $\alpha_{\rm{s}}^{\rm{eff}}$. Our result shows that this effective charge freezes, i.e. loses its scale dependence, at long (nucleon-size) distances. This finite behavior allows us to obtain a physical coupling constant for the strong interaction that is relevant at all scales.

Download or read book Comparison of e annihilation with QCD and determination of the strong coupling constant written by and published by . This book was released on 1980 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Jet Physics in Ee Annihilation written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The energy dependence of the relative production rate of 3-jet events is studied in hadronic ee− annihilation events at centre of mass energies between 22 and 56 GeV, using the data of the JADE, MARK-II and AMY collaborations at PETRA, PEP and TRISTAN. Three jet events are defined by a jet finding algorithm which is closely related to the definition of resolvable jets used in O(.cap alpha./sub s/2) perturbative QCD calculations, where the relative production rate of 3-jet events is roughly proportional to the strong coupling strength, .cap alpha./sub s/. The observed production rates of 3-jet events decreases significantly with increasing centre of mass energy. The results, which are independent of fragmentation model calculations, can be directly compared to theoretically calculated jet production rates and are in good agreement with the QCD expectations of a running coupling strength, while the hypothesis of an energy independent coupling constant can be excluded with a significance of 5 standard deviations. Based on these results, the presented jet analysis also provides the possibility to detect first signs of the production of new and heavy particles in the early stage of data taking at SLC and LEP.

Download or read book Measurement of the Total Hadronic Cross Section Ee Annihilation at square Root Of S written by Christoph von Zanthier and published by . This book was released on 1990 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Determination of the Effective Strong Coupling Constant written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We extract an effective strong coupling constant from low Q2 data on the Bjorken sum. Using sum rules, we establish its Q2-behavior over the complete Q2-range. The result is compared to effective coupling constants extracted from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constant and the calculations is not clear, the results agree surprisingly well.

Download or read book Measurement of alpha sub S in Ee Annihilation at E sub Cm written by and published by . This book was released on 1994 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: A measurement of the strong coupling constant [alpha]{sub s} using the event-shape variable y3 (the differential two-jet rate) in the reaction ee− 2!hadrons is presented. The analysis is based on data from the TPC/Two-Gamma detector at the PEP e+e− storage ring taken between 1984 and 1986 at a center-of-mass energy of E{sub cm} = 29 GeV. A value of [alpha]{sub s}(29 GeV) = 0.160 ± 0.012 is obtained, where the error is the quadratic sum of experimental and theoretical uncertainties. The procedure for determining [alpha]{sub s} is the same as that used by the ALEPH and TOPAZ experiments, which allows for a consistent comparison of the [alpha]{sub s} values obtained at different center-of-mass energies. The observed energy dependence {open_quotes}running{close_quotes} of [alpha]{sub s} is found to be in good agreement with the QCD prediction, and is clearly incompatible with a constant value.

Download or read book Precise Tests of QCD in Ee Annihilation written by and published by . This book was released on 1997 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: A pedagogical review is given of precise tests of QCD in electron-positron annihilation. Emphasis is placed on measurements that have served to establish QCD as the correct theory of strong interactions, as well as measurements of the coupling parameter [alpha]{sub s}. An outlook is given for future important tests at a high-energy ee− collider.

Download or read book Theory of Jets in Electron Positron Annihilation written by G. Kramer and published by Springer. This book was released on 2006-04-11 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: