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We discuss the effects of the $s$-channel unitarization on the $x$ and $Q^{2}$ dependence of structure functions. The unitarization is implemented at the level of photoabsorption cross sections by resorting to the light--cone wave functions…

High Energy Physics - Phenomenology · Physics 2009-10-22 V. Barone , M. Genovese , N. N. Nikolaev , E. Predazzi , B. G. Zakharov

Radiatively generated, LO quark (u,d,s,c,b) and gluon densities in the real, unpolarized photon, improved in respect to our previous paper, are presented. We perform three global fits to the F_2^gamma data, using the LO DGLAP evolution…

High Energy Physics - Phenomenology · Physics 2014-11-17 F. Cornet , P. Jankowski , M. Krawczyk

The forward elastic amplitude for scattering of real and weakly virtual photons is studied in the framework of the theory of reggeized gluons, with large $N_{c}$ and a running coupling constant introduced in the manner which preserves the…

High Energy Physics - Phenomenology · Physics 2009-10-28 M. A. Braun

The complete relativistic $O(\alpha^2)$ nuclear structure correction to the energy levels of ordinary (electronic) and muonic hydrogen-like atoms is investigated. The elastic part of the nuclear structure correction is derived analytically.…

Atomic Physics · Physics 2018-06-29 Krzysztof Pachucki , Vojtěch Patkóš , Vladimir A. Yerokhin

We summarize recent results on the evolution of unpolarized parton densities and deep-inelastic structure functions in massless perturbative QCD. Due to last year's extension of the integer-moment calculations of the three-loop splitting…

High Energy Physics - Phenomenology · Physics 2008-11-26 W. L. van Neerven , A. Vogt

We briefly discuss recent results on the evolution of unpolarized parton densities and structure functions in massless perturbative QCD. Present partial results on the next-to-next-to-leading order (NNLO) evolution kernels prove sufficient…

High Energy Physics - Phenomenology · Physics 2009-10-31 W. L. van Neerven , A. Vogt

We perform the NLO QCD analysis of the world data on inclusive deep inelastic scattering cross sections of charged leptons off the proton and the deuterium targets. The parton distributions, the value of strong coupling constant…

High Energy Physics - Phenomenology · Physics 2007-05-23 Alekhin Sergey

Parameter-free and perturbatively stable leading order (LO) and next-to-leading order (NLO) parton densities for real and virtual photons are presented.

High Energy Physics - Phenomenology · Physics 2007-05-23 I. Schienbein

The computation of exclusive QCD jet observables at higher orders requires a method for the subtraction of infrared singular configurations arising from multiple radiation of real partons. One commonly used method at next-to-leading order…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Gehrmann--De Ridder , T. Gehrmann , E. W. N. Glover

I present a calculation of structure functions at leading order which includes an unambiguous inclusion of the leading ln(1/x) terms for each power of alpha_s, and also the correct effects due to the mass of the charm and bottom quarks. I…

High Energy Physics - Phenomenology · Physics 2007-05-23 R. S. Thorne

Recent measurements of unpolarised and polarised nucleon structure functions and F_2(gamma) are reviewed. The implications for QCD and the gluon momentum distribution are discussed. The status of the understanding of the total…

High Energy Physics - Experiment · Physics 2007-05-23 Robin Devenish

In the large-momentum effective field theory approach to parton physics, the matrix elements of non-local operators of quark and gluon fields, linked by straight Wilson lines in a spatial direction, are calculated in lattice quantum…

High Energy Physics - Phenomenology · Physics 2018-03-21 Xiangdong Ji , Jian-Hui Zhang , Yong Zhao

The photon impact factor for the BFKL pomeron is calculated in the next-to-leading order (NLO) approximation using the operator expansion in Wilson lines. The result is represented as a NLO $k_T$-factorization formula for the structure…

High Energy Physics - Phenomenology · Physics 2014-07-29 Ian Balitsky , Giovanni A. Chirilli

Deep inelastic structure functions for the nucleon are obtained in a constituent quark model on the light cone. Parton model formulas are derived. The negative slope of $F_{2}^{n}/F_{2}^{p} requires attraction between scalar quark pairs.…

High Energy Physics - Phenomenology · Physics 2009-10-28 H. J. Weber

We propose a general form of the UV-completed Friedberg-Lee-Sirlin (FLS) model. As can be seen from the mechanical interpretation, UV-completion allows thin-wall approximation for non-topological solitons. The 1-loop renormalized effective…

High Energy Physics - Phenomenology · Physics 2024-05-16 Eduard Kim , Emin Nugaev , Yakov Shnir

We show how the parton distributions in the photon can be accurately measured in the photoproduction of large-pt jets at HERA. A short review is given of the beyond Leading Logarithm formalism for the photon structure function, with a…

High Energy Physics - Phenomenology · Physics 2009-09-25 M. Fontannaz

We present a systematic analysis of the polarised and unpolarised processes $e^+ ~e^- \rightarrow e^+ ~e^- X$ in the deep inelastic limit and study the effects of target photon mass (virtuality) on the photon structure functions. The effect…

High Energy Physics - Phenomenology · Physics 2007-05-23 Prakash Mathews , V. Ravindran

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 compute the full three-loop coefficient functions for the structure functions F_2 and F_L in massless perturbative QCD. The results for F_L complete the next-to-next-to-leading order description of unpolarized electromagnetic…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. A. M. Vermaseren , A. Vogt , S. Moch

The current status of measurements of the nucleon structure functions and their understanding is reviewed. The fixed target experiments E665, CCFR and NMC and the HERA experiments H1 and ZEUS are discussed in some detail. The extraction of…

High Energy Physics - Phenomenology · Physics 2010-03-25 A. M. Cooper-Sarkar , R. C. E. Devenish , A. De Roeck