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Recent progress in the understanding of the nucleon is presented. The unpolarised structure functions are obtained with unprecedented precision from the combined H1 and ZEUS data and are used to extract proton parton distribution functions…

High Energy Physics - Experiment · Physics 2009-03-27 Cristinel Diaconu

QCD-inspired phenomenological analysis of experimental moments of proton and deuteron structure functions F2 have been presented. The obtained results on the d/u ratio at large-x, isospin dependence of higher twists and comparison with…

High Energy Physics - Phenomenology · Physics 2007-11-14 M. Osipenko

We calculate the contribution from the $q \bar q g$ state production to the diffractive cross sections in deep inelastic scattering at high energy. The obtained cross section is finite by itself and a part of the full next-to-leading order…

High Energy Physics - Phenomenology · Physics 2022-11-23 G. Beuf , H. Hänninen , T. Lappi , Y. Mulian , H. Mäntysaari

Structure function measurements of the proton, the photon, and of colour singlet exchange are analysed using fits based on logarithmic Q**2-dependence. The fits reveal the x-dependencies of the hadronic structures and the interaction…

High Energy Physics - Experiment · Physics 2009-10-31 Martin Erdmann

The leading effect of light gluinos on the deep inelastic longitudinal structure function is calculated. We present the explicit analitic expression for the Wilson coefficient. After convolution with quark, gluon and gluino distributions we…

High Energy Physics - Phenomenology · Physics 2009-10-28 A. V. Kotikov , G. Parente , O. A. Sampayo

We discuss the longitudinal structure function in nuclear DIS at small $x$. We work within the framework of universal parton densities obtained in DGLAP analyses at NLO. We show that the nuclear effects on the longitudinal structure…

High Energy Physics - Phenomenology · Physics 2014-11-21 N. Armesto , H. Paukkunen , C. A. Salgado , K. Tywoniuk

The $F_2$, $F_G$, $R = F_L/F_T$ proton structure functions are derived in the QCD dipole picture. Assuming $k_T$ and renormalization-group factorization, we relate deep-inelastic proton scattering to deep-inelastic onium scattering. We get…

High Energy Physics - Phenomenology · Physics 2008-11-26 H. Navelet , R. Peschanski , Ch. Royon , S. Wallon

Two component model for a description of the electromagnetic nucleon structure functions in low-x region, based on generalized vector dominance and color dipole approaches is briefly described. The model operates with the mesons of…

High Energy Physics - Phenomenology · Physics 2009-12-08 E. V. Bugaev , B. V. Mangazeev

A QCD analysis of the nuclear parton distributions and structure functions in the NLO is performed by using the world data. By having bounded parton distributions for a nuclear with atomic number A, we can obtain the nuclear structure…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. Atashbar Tehrani , Ali N. Khorramian

We present a global fit to the structure function F_2 measured in lepton-proton experiments at small values of Bjorken-x, x< 0.01, for all experimentally available values of Q^2, 0.045< Q^2 < 800 GeV^2, using the Balitsky -Kovchegov…

High Energy Physics - Phenomenology · Physics 2009-06-16 J. L. Albacete , N. Armesto , J. G. Milhano , C. A. Salgado

We analytically solved the QED $\otimes$ QCD coupled DGLAP evolution equations at leading order (LO) quantum electrodynamics (QED) and next to leading order (NLO) quantum chromodynamics (QCD) approximations, using the Laplace transform…

High Energy Physics - Phenomenology · Physics 2017-07-07 Marzieh Mottaghizadeh , Parvin Eslami , Fatemeh Taghavi-Shahri

New results from the H1 and ZEUS collaborations on the measurement of cross-sections at very high Q^2 (up to 25000 GeV^2) and on the proton structure function F_2(x,Q^2) for momentum transfers squared Q^2 >= 1.5 GeV^2 and Bjorken x >= 3.5…

High Energy Physics - Experiment · Physics 2007-05-23 Gregorio Bernardi

The logarithmic and constant contributions to the Wilson coefficient of the longitudinal heavy quark structure function to $O(\alpha_s^3)$ are calculated using mass factorization techniques in Mellin space. The small $x$ behaviour of the…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. Blümlein , A. De Freitas , W. L. van Neerven , S. Klein

In this paper, the proton structure function $F_2 ^p (x,Q^2)$ at small-$x$ is investigated using an analytical solution of the Balitsky-Kovchegov (BK) equation. In the context of the color dipole description of deep inelastic scattering…

High Energy Physics - Phenomenology · Physics 2024-03-21 Ranjan Saikia , Pragyan Phukan , Jayanta Kumar Sarma

We computed the longitudinal proton structure function $F_{L}$, using the nonlinear Dokshitzer-Gribov-Lipatov-Altarelli-parisi (NLDGLAP) evolution equation approach at small $x$. For the gluon distribution, the nonlinear effects are related…

High Energy Physics - Phenomenology · Physics 2014-02-07 G. R. Boroun

A semiclassical description of structure functions in DIS at small $x$ is presented. It gives an intuitive picture of the transition from the Double Leading Log approximation at large $Q^2$, to the powerlike dependence on $x$ in the BFKL…

High Energy Physics - Phenomenology · Physics 2016-08-16 Gösta Gustafson

In many calculations involving polarized twist-2 parton densities to higher order in the strong coupling constant one uses the Larin scheme to describe chiral effects in dimensional regularization. Upon forming observables, the scheme…

High Energy Physics - Phenomenology · Physics 2024-05-28 J. Blümlein , M. Saragnese

The first measurements of the diffractive structure function $F_2^{D(3)}$ at HERA are discussed. A factorisable interpretation in which a partonic structure is assigned to the pomeron is investigated through QCD analyses in which both the…

High Energy Physics - Phenomenology · Physics 2008-11-26 K. Golec-Biernat , J. P. Phillips

We make predictions for the diffractive longitudinal structure function F_L^D to be measured at HERA, based on DGLAP fits of diffractive parton distributions with twist--4 contribution. This contribution describes diffractive qqbar…

High Energy Physics - Phenomenology · Physics 2007-11-20 Krzysztof Golec-Biernat , Agnieszka Luszczak

We review small $x$ contributions to perturbative evolution equations for parton distributions, and their resummation. We emphasize in particular the resummation technique recently developed in order to deal with the apparent instability of…

High Energy Physics - Phenomenology · Physics 2007-05-23 Guido Altarelli , Richard D. Ball , Stefano Forte