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Related papers: The Photon Structure Function at Small-x

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We present our analysis on the photon structure functions at small Bjorken variable x in the framework of the holographic QCD. In the kinematic region, a photon can fluctuate into vector mesons and behaves like a hadron rather than a…

High Energy Physics - Phenomenology · Physics 2016-12-21 Akira Watanabe , Hsiang-nan Li

We study photon--meson transition form factors $\gamma^*(Q^2)\gamma \to \pi^0,\eta,\eta'$ at low and moderately high virtualities $Q^2$ of one of the photons, the second photon being real. For the description of the form factor at low…

High Energy Physics - Phenomenology · Physics 2009-10-28 V. V. Anisovich , D. I. Melikhov , V. A. Nikonov

Polarized photon structure can be studied in the future polarized $e^{+}e^{-}$ colliding-beam experiments. We investigate the spin-dependent structure function of the virtual photon $g_1^{\gamma}(x,Q^2,P^2)$, in perturbative QCD for…

High Energy Physics - Phenomenology · Physics 2016-08-25 Ken Sasaki , Tsuneo Uematsu

We show that simple parametrisations at small x of the proton structure function work so well in limited regions of the $(x,Q^2)$ plane because they are approximately "self-consistent" solutions of the QCD evolution equation. For a class of…

High Energy Physics - Phenomenology · Physics 2022-03-02 L. L. Jenkovszky , A. Lengyel , F. Paccanoni

The organization of finite order QCD approximations to $F_2^{\gamma}(x,Q^2)$ based on the separation of pure QED contribution from those of genuine QCD nature is discussed.

High Energy Physics - Phenomenology · Physics 2009-02-12 Jiri Chyla

We present a set of formulas to extract the ratio $F_{L}(x,Q^{2})/F_{2}(x,Q^{2})$ and $R(x,Q^{2})$ from the proton structure function parameterized in the next-to-next-to-leading order of the perturbative theory at low $x$ values. The…

High Energy Physics - Phenomenology · Physics 2020-06-29 B. Rezaei , G. R. Boroun

In the framework of conventional Regge theory we present a common description of total photon-proton cross-section and proton structure functions in the region $0 \leq Q^2 \leq 5 \ {\rm GeV}^2$. Using it as an initial condition in the…

High Energy Physics - Phenomenology · Physics 2009-10-28 A. Capella , A. Kaidalov , C. Merino , J. Tran Thanh Van

Muon pair production in the process e+e- -> e+e-mu+mu- is studied using the data taken at LEP1 (sqrt(s) \simeq m_Z) with the DELPHI detector during the years 1992-1995. The corresponding integrated luminosity is 138.5 pb^{-1}. The QED…

High Energy Physics - Experiment · Physics 2010-04-08 The DELPHI Collaboration , P. Abreu

Recent data on the structure function F_2(x,Q^2) at small values of x are analysed and compared with theoretical expectations. It is shown that the observed rise at small x is consistent with a logarithmic increase, growing logarithmically…

High Energy Physics - Phenomenology · Physics 2007-05-23 W. Buchmuller , D. Haidt

A reanalysis of the model for the longitudinal structure function $F_L (x,Q^2)$ at low $x$ and low $Q^2$ was undertaken, in view of the advent of the EIC. The model is based on the photon-gluon fusion mechanism suitably extrapolated to the…

High Energy Physics - Phenomenology · Physics 2022-04-20 B. Badelek , A. M. Stasto

The QCD structure of the electroweak bosons is reviewed and the lepton structure function is defined and calculated. The leading order splitting functions of electron into quarks are extracted, showing an important contribution from…

High Energy Physics - Phenomenology · Physics 2007-05-23 Wojciech Slominski , Jerzy Szwed

The gluon contributions to $F_L(x,Q^2)$ in ${\cal O}(\alpha_s)$ are calculated taking into account the transverse momentum of the initial state parton. In comparison with collinear factorization $F_L(x,Q^2)$, is not affected at large $x$…

High Energy Physics - Phenomenology · Physics 2009-10-28 Johannes Blümlein

Present data on the partonic content of the photon are reviewed. The results on the unpolarized structure functions from DIS experiments and on large pt jet production processes in gamma-gamma and gamma-p collisions are discussed for both…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Krawczyk , M. Staszel , A. Zembrzuski

We study the three positivity constraints among the eight virtual photon structure functions, derived from the Cauchy-Schwarz inequality and which are hence model-independent. The photon structure functions obtained from the simple parton…

High Energy Physics - Phenomenology · Physics 2009-11-07 Ken Sasaki , Jacques Soffer , Tsuneo Uematsu

We investigate the polarized photon structure functions $g_1^\gamma$ and $g_2^\gamma$ which can be studied in the future polarized version of ep or e$^+$e$^-$ colliders. The NLO QCD calculations of $g_1^\gamma$ and the possible twist-3…

High Energy Physics - Phenomenology · Physics 2009-11-07 Hideshi Baba , Ken Sasaki , Tsuneo Uematsu

In deep inelastic electron-photon scattering in leading order QED, egamma->egamma*gamma->effbar, there are four non-zero structure functions. We calculate them for real photons retaining the full dependence on the fermion mass, and show…

High Energy Physics - Phenomenology · Physics 2009-10-31 Richard Nisius , Michael H. Seymour

We predict the effect of the charm structure function on the longitudinal structure function at small x. In NLO analysis we find that the hard Pomeron behavior gives a good description of $F_{L}$ and $F^{c}_{k}$ (k = 2,L) at small x values.…

High Energy Physics - Phenomenology · Physics 2015-06-18 B. Rezaei , G. R. Boroun

Factorization scheme analysis of $F_2^{\gamma}(x,Q^2)$ in the next-to-leading order QCD is revisited. It is emphasized that the presence of the inhomogeneous term in the evolution equations for quark distribution functions of the photon…

High Energy Physics - Phenomenology · Physics 2007-05-23 Jiri Chyla

Nuclear structure functions at small x and small or moderate $Q^2$ are studied using the relation with diffraction on nucleons which arises from Gribov's Reggeon Calculus. A reasonable description of experimental data is obtained with no…

High Energy Physics - Phenomenology · Physics 2011-09-13 N. Armesto , A. Capella , A. B. Kaidalov , J. Lopez-Albacete , C. A. Salgado