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Related papers: Hadronic Component of the Photon Spin Dependent St…

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The spin dependent structure function, g2ww(x,Q^2), is calculated in the valon model. A simple approach is given for the determination of the twist-3 part of the g2(x, Q^2) in Mellin space; thus, enabling us to obtain the full transverse…

High Energy Physics - Phenomenology · Physics 2015-08-13 Z. Alizadeh Yazdi , A. Tahamtan , F. Taghavi-Shahri , F. Arash , M. E. Zomorrodian

The measurements of hadronic structure functions of the photon based on the reaction ee --> ee gamma^(*)(P^2) gamma^*(Q^2)--> ee hadrons are discussed.

High Energy Physics - Experiment · Physics 2007-05-23 Richard Nisius , Daniel Haas , Claus Grupen

The hadronic structure of the photon F2gamma is measured as a function of Bjorken x and of the photon virtuality Q2 using deep-inelastic scattering data taken by the OPAL detector at LEP at e+e- centre-of-mass energies from 183 to 209 GeV.…

High Energy Physics - Experiment · Physics 2008-11-26 The OPAL collaboration , G. Abbiendi

The hadronic structure function of the photon F_2^gamma is measured as a function of Bjorken x and of the factorisation scale Q^2 using data taken by the OPAL detector at LEP. Previous OPAL measurements of the x dependence of F_2^gamma are…

High Energy Physics - Experiment · Physics 2017-08-23 R. J. Taylor

We calculate the contribution from the $q\bar{q}g$ component of a virtual photon state to the small-$x$ diffractive cross section in deep inelastic scattering in the saturation regime. The obtained cross section is finite by itself and a…

High Energy Physics - Phenomenology · Physics 2023-05-26 G. Beuf , H. Hänninen , T. Lappi , H. Mäntysaari , Y. Mulian

Spin-dependent parton distributions in the polarized virtual photon are investigated in QCD up to the next-to-leading order (NLO). In the case $\Lambda^2 \ll P^2 \ll Q^2$, where $-Q^2$ ($-P^2$) is the mass squared of the probe (target)…

High Energy Physics - Phenomenology · Physics 2009-10-31 Ken Sasaki , Tsuneo Uematsu

Present data on the partonic content of the photon from LEP, TRISTAN and HERA accelerators are reviewed and the essential aspects of the underlying ideas and methods are pointed out. Results of the unpolarized photon structure function F_2…

High Energy Physics - Phenomenology · Physics 2014-11-17 Maria Krawczyk , Magdalena Staszel , Andrzej Zembrzuski

The present knowledge of the structure of the photon is presented based on results obtained by measurements of photon structure functions at e+e- collider. Results are presented both for the QED structure of the photon as well as for the…

High Energy Physics - Experiment · Physics 2009-07-17 Richard Nisius

We present the results of our final analysis of the full data set of g_1^p(Q^2), the spin structure function of the proton, collected using CLAS at Jefferson Lab in 2000-2001. Polarized electrons with energies of 1.6, 2.5, 4.2 and 5.7 GeV…

Development of concepts related to the photon and its high energy hadronic interaction is briefly reviewed. A photon considered as an ideal probe of hadron structure, paradoxically is also considered as an ideal target to test the…

High Energy Physics - Phenomenology · Physics 2009-10-31 Maria Krawczyk

On the grounds of extension of the U-matrix unitarization to the off-shell scattering we consider virtual-photon induced scattering. We discuss behavior of the structure function F_2(x,Q^2) at low x and the total cross-section of…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. M. Troshin , N. E. Tyurin

We discuss target mass effects in the polarized virtual photon structure functions $g_1^\gamma (x,Q^2,P^2)$, $g_2^\gamma (x,Q^2,P^2)$ for the kinematic region $\Lambda^2\ll P^2 \ll Q^2$, where $-Q^2 (-P^2)$ is the mass squared of the probe…

High Energy Physics - Phenomenology · Physics 2009-11-10 Ken Sasaki , Tsuneo Uematsu

We calculate the spin dependent structure functions g_{1}(x) and g_{2}(x) of the proton and neutron. Our calculation uses the meson cloud model of nucleon structure, which has previously given a good description of the HERMES data on…

High Energy Physics - Phenomenology · Physics 2008-11-26 F. Bissey , F. G. Cao , A. I. Signal

The possibility is investigated to measure the polarized structure function $g_1(x,Q^2)$ in the collider mode of HERA operating with a polarized lepton and proton beam. The $x$ dependence of $g_1$ can be measured at a statistical precision…

High Energy Physics - Phenomenology · Physics 2008-02-03 Johannes Blümlein

Recent improvements in the analysis techniques and Monte Carlo models used in the measurement of the hadronic structure function of the photon have lead to much improved experimental results. Its low x behaviour was studied in various Q^2…

High Energy Physics - Experiment · Physics 2007-05-23 Akos Csilling

Photon structure functions in supersymmetric QCD are investigated in terms of the parton model where squark contributions are evaluated. We calculate the eight virtual photon structure functions by taking the discontinuity of the squark…

High Energy Physics - Phenomenology · Physics 2013-05-29 Yoshio Kitadono , Ryo Sahara , Tsuneo Uematsu , Yutaka Yoshida

Spin-polarizabilities are predicted by calculating the cross-section difference $\sigma_{3/2}-\sigma_{1/2}$ from available data for the resonance couplings $A_{3/2}$ and $A_{1/2}$ and CGLN amplitudes. The forward spin-polarizabilities are…

High Energy Physics - Phenomenology · Physics 2013-06-26 Martin Schumacher , M. I. Levchuk

The theoretical framework for a next-to-leading order QCD analysis of the spin-dependent parton densities Delta f^{gamma}(x,Q^2) of the longitudinally polarized photon and of its structure function g_1^{gamma}(x,Q^2) is reviewed in some…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Stratmann

We present a systematic analysis of the processes $e^+ ~e^- \rightarrow e^+ ~e^- X$ to study the polarised and unpolarised photon structure functions. The effect of target photon mass, which manifests itself as new singly polarised…

High Energy Physics - Phenomenology · Physics 2015-06-25 Prakash Mathews , V. Ravindran

The present knowledge of the structure of the photon based on measurements of photon structure functions is discussed. This review covers QED structure functions and the hadronic structure function F_2^gamma.

High Energy Physics - Experiment · Physics 2007-05-23 Richard Nisius