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Related papers: $R_{e^+ e^-}$ and an effective QCD charge

200 papers

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…

High Energy Physics - Phenomenology · Physics 2007-05-23 Sergio Lupia

Three-photon annihilation of the electron-positron pairs (= $(e^{-}, e^{+})-$pairs) is considered in the electron rest frame. The energy of the incident positron can be arbitrary. The analytical expression for the cross-section of…

High Energy Physics - Theory · Physics 2009-05-08 A. M. Frolov

We analyze experimental data for the production of Lambda baryons in e^+e^- annihilation in terms of scale dependent, QCD evolved, Lambda fragmentation functions. Apart from the vast majority of the data for which the polarization of an…

High Energy Physics - Phenomenology · Physics 2009-10-30 D. de Florian , M. Stratmann , W. Vogelsang

We have reevaluated the hadronic contribution to the anomalous magnetic moment of the muon (g-2) and to the running of the QED fine structure constant alpha(s) at s=M_Z**2. We incorporated new data from hadronic tau decays, recently…

High Energy Physics - Phenomenology · Physics 2008-11-26 R. Alemany , M. Davier , A. Hocker

It was shown that at typical energies and luminosities of an $e^+e^-$ linear collider one can observe a significant suppression of fluctuations of the number of gluons in small angular regions. This property of jets is expected in $e^+e^-$…

High Energy Physics - Phenomenology · Physics 2009-11-07 S. V. Chekanov

We compute the photon emission rate of an equilibrated, hot QCD plasma at zero chemical potential, to leading order in both alpha_{EM} and the QCD coupling g_s(T). This requires inclusion of near-collinear bremsstrahlung and inelastic pair…

High Energy Physics - Phenomenology · Physics 2010-02-03 Peter Arnold , Guy D. Moore , Laurence G. Yaffe

The ${\cal O}(\alpha_s^2)$ coefficient of the energy-energy correlation function (EEC) has been calculated by four groups with differing results. This discrepancy has lead to some confusion over how to measure the strong coupling constant…

High Energy Physics - Phenomenology · Physics 2008-11-26 E. W. N. Glover , M. R. Sutton

We present new sets of fragmentation functions in next-to-leading order QCD that are determined from e+e- annihilation data of inclusive particle production. In addition to the O(alpha_s) unpolarized cross section the longitudinal cross…

High Energy Physics - Phenomenology · Physics 2007-05-23 Janko Binnewies

In this paper the nuclear configurational entropy of the energy--energy correlation function is scrutinized, in $e^+e^-$ collisions to hadrons in the back-to-back region, within the QCD perturbative theory. The critical points of the…

High Energy Physics - Phenomenology · Physics 2019-05-22 G. Karapetyan

The fully resummed next-to-leading-order perturbative calculation of the energy-energy correlation in $e^+e^-$ annihilation is extended to include the leading non-perturbative power-behaved contributions computed using the ``dispersive…

High Energy Physics - Phenomenology · Physics 2014-11-17 Yu. L. Dokshitzer , G. Marchesini , B. R. Webber

We perform a simultaneous global analysis of hadron fragmentation functions (FFs) to various charged hadrons at next-to-leading order in QCD. The world data set includes results from electron-positron single-inclusive annihilation,…

High Energy Physics - Phenomenology · Physics 2024-07-02 Jun Gao , ChongYang Liu , XiaoMin Shen , Hongxi Xing , Yuxiang Zhao

An investigation of the polar angle distribution of charged hadrons is presented using data taken by the JADE experiment at the PETRA e^+e^- collider at centre-of-mass energies of 35 and 44 GeV. From fits to the polar angle distribution the…

High Energy Physics - Experiment · Physics 2014-11-17 M. Blumenstengel , O. Biebel , P. A. Movilla Fernandez , P. Pfeifenschnedier , S. Bethke , S. Kluth , the JADE Collaboration

In this contribution to the proceedings, we analyze the transition from perturbative and non- perturbative QCD embedded in the coupling constant. In the study of quark-hadron duality, we suggest that the realization of the latter is related…

High Energy Physics - Phenomenology · Physics 2013-12-04 A. Courtoy

We calculate the 1-loop $\gamma Z$ box-graph correction to electron-quark scattering at low energy and low momentum transfer. Both electron and quark masses are kept non-zero. From our result, we extract coupling constants for the…

High Energy Physics - Phenomenology · Physics 2026-01-21 Balma Duch , Pere Masjuan , Hubert Spiesberger

In this paper, the reaction of electron-positron annihilation into $\Lambda_c^+\bar{\Lambda}_c^-$ is investigated. The $\Lambda_c^+\bar{\Lambda}_c^-$ scattering amplitudes are obtained by solving the Lippmann-Schwinger equation. The…

High Energy Physics - Phenomenology · Physics 2024-04-10 Di Guo , Qin-He Yang , Ling-Yun Dai

A model independent formalism for the electron positron annihilation reaction $e^++e^-\to a_1(1260)+\pi $ has been derived. The differential and total cross sections and the elements of the spin--density matrix of the $a_1$-meson were…

High Energy Physics - Phenomenology · Physics 2008-11-26 E. Tomasi-Gustafsson , G. I. Gakh , C. Adamuščín

Compton scattering provides important insight into the structure of the nucleon. For photons up to about 300 MeV, it is parameterised by six dynamical dipole polarisabilities which characterise the response of the nucleon to a monochromatic…

Nuclear Theory · Physics 2012-12-12 Harald W. Griesshammer , Judith A. McGovern , Daniel R. Phillips , Gerald Feldman

Electromagnetic polarizabilities are important parameters for understanding the interaction between photons and hadrons. For pions these quantities are poorly constrained experimentally since they can only be measured indirectly. New…

High Energy Physics - Lattice · Physics 2016-02-17 Andrei Alexandru , Michael Lujan , Walter Freeman , Frank Lee

We propose a method for measuring the hadron charge asymmetry in $\ee$ collisions which is based upon the fragmentation function formalism, and is largely independent of modelling of fragmentation effects. Furthermore, in this method, QCD…

High Energy Physics - Phenomenology · Physics 2009-10-28 P. Nason , B. W. Webber

In the framework of quark-hadron duality, the cross section values of charmonium and doubly charmed baryon production in $e^+e^-$-annihilations have been estimated at interaction energy $\sqrt{s}=10.6$ GeV. It has been shown that the…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. V. Berezhnoy , A. K. Likhoded