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We recall our recent description of quark parton densities of the proton at $Q^2=4 GeV^2$ in terms of Fermi-Dirac distributions parametrized with very few free parameters. We have also proposed some simple assumptions to relate unpolarized…

High Energy Physics - Phenomenology · Physics 2016-09-01 Claude Bourrely , Jacques Soffer

We present the coefficient functions for deep-inelastic scattering (DIS) via the exchange of a scalar phi directly coupling only to gluons, such as the Higgs boson in the limit of a very heavy top quark and n_f effectively massless light…

High Energy Physics - Phenomenology · Physics 2014-11-20 G. Soar , A. Vogt , S. Moch , J. Vermaseren

Nuclear parton distributions $f_A(x,Q^2)$ are studied within a framework of the DGLAP evolution. Measurements of $F_2^A/F_2^D$ in deep inelastic $lA$ collisions, and Drell--Yan dilepton cross sections measured in $pA$ collisions are used as…

High Energy Physics - Phenomenology · Physics 2015-06-25 K. J. Eskola , V. J. Kolhinen , P. V. Ruuskanen , C. A. Salgado

Determination of proton parton distribution functions is present under the dynamical parton model assumption by applying DGLAP equations with GLR-MQ-ZRS corrections. We provide two data sets, referred as IMParton16, which are from two…

High Energy Physics - Phenomenology · Physics 2017-04-03 Rong Wang , Xurong Chen

In the semiclassical approach, inclusive and diffractive quark and gluon distributions are expressed in terms of correlation functions of Wilson loops. Each Wilson loop integrates the colour field strength in the area between the…

High Energy Physics - Phenomenology · Physics 2010-03-25 W. Buchmuller , T. Gehrmann , A. Hebecker

We analyze deep inelastic scattering at small Bjorken x, using the approximate conformal invariance of QCD at high energies. Hard pomeron exchanges are resummed eikonally, restoring unitarity at large values of the phase shift in the dual…

High Energy Physics - Phenomenology · Physics 2009-03-19 Lorenzo Cornalba , Miguel S. Costa

Using an analytical parameterization for the behavior of the x slope of the structure function F_2 at small x in perturbative QCD, at the leading twist approximation of the Wilson operator product expansion, and applying a flat initial…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. V. Kotikov , G. Parente

The $Q^2$ dependence of the ratios of nuclear structure functions $F_2^A$ is studied by performing QCD evolution of nuclear parton distribution functions. The log $Q^2$ slope of these ratios is very sensitive to the nuclear gluon…

High Energy Physics - Phenomenology · Physics 2007-05-23 K. J. Eskola , H. Honkanen , V. J. Kolhinen , C. A. Salgado

We study the effect of gluon number fluctuations (Pomeron loops) on deep inelastic scattering (DIS) in the fixed coupling case. We find that the description of the DIS data is improved once gluon number fluctuations are included. Also the…

High Energy Physics - Phenomenology · Physics 2009-11-13 Misha Kozlov , Arif Shoshi , Wenchang Xiang

We formulate and numerically solve the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi~(DGLAP) evolution equations at next-to-leading order in perturbation theory directly for a basis of 6 physical, observable structure functions in deeply…

High Energy Physics - Phenomenology · Physics 2025-09-03 Tuomas Lappi , Heikki Mäntysaari , Hannu Paukkunen , Mirja Tevio

The status of measurements and interpretation of the proton structure function F2 is summarized. The measurements are subjected to DGLAP fits, from which the gluon density is extracted and a comparison to measurements of F2c is performed.…

High Energy Physics - Experiment · Physics 2016-11-23 Christoph Amelung

The contribution of quarks with masses m >> Lambda_QCD is the only part of the structure functions in deep-inelastic scattering (DIS) which is not yet known at the next-to-next-to-leading order (NNLO) of perturbative QCD. We present…

High Energy Physics - Phenomenology · Physics 2016-08-09 H. Kawamura , N. A. Lo Presti , S. Moch , A. Vogt

We perform a global parton analysis of deep inelastic and related hard-scattering data, including ${\cal O}(\alpha_{\rm QED})$ corrections to the parton evolution. Although the quality of the fit is essentially unchanged, there are two…

High Energy Physics - Phenomenology · Physics 2010-03-25 A. D. Martin , R. G. Roberts , W. J. Stirling , R. S. Thorne

We investigate the importance of unitarity corrections to parton evolution in heavy flavor production at the LHC. The gluon distribution is determined with a fit to HERA data applying a unified BFKL-DGLAP approach, in which the non-linear…

High Energy Physics - Phenomenology · Physics 2017-08-23 Krisztian Peters

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

We address a long standing problem concerning the scale behaviour of parton densities in the low $x$, low $Q^2$ domain. We emphasize the important role of absorptive corrections at low $x$ and use knowledge of diffractive deep inelastic…

High Energy Physics - Phenomenology · Physics 2019-01-30 M. R. Pelicer , E. G. de Oliveira , A. D. Martin , M. G. Ryskin

We obtain a good analytic fit to the joint Bjorken-x and Q^2 dependences of ZEUS data on the deep inelastic structure function F_2(x, Q^2). At fixed virtuality Q^2, as we showed previously, our expression is an expansion in powers of log…

High Energy Physics - Phenomenology · Physics 2008-11-26 Edmond L. Berger , M. M. Block , Chung-I Tan

A measurement of the derivative (d ln F_2 / d lnx)_(Q^2)= -lambda(x,Q^2) of the proton structure function F_2 is presented in the low x domain of deeply inelastic positron-proton scattering. For 5*10^(-5)<=x<=0.01 and Q^2>=1.5 GeV^2,…

High Energy Physics - Experiment · Physics 2010-03-25 H1 Collaboration , C. Adloff

We present an introductory discussion of deep-inelastic lepton-proton scattering as a means to probe the substructure of the proton. A resume of QCD is given, emphasizing the running of the coupling constant and the DGLAP evolution…

High Energy Physics - Phenomenology · Physics 2010-03-25 Alan D. Martin

Parton distributions can be defined in terms of the entropy of entanglement between the spatial region probed by deep inelastic scattering (DIS) and the rest of the proton. For very small $x$, the proton becomes a maximally entangled state.…

High Energy Physics - Phenomenology · Physics 2021-09-08 Dmitri E. Kharzeev , Eugene Levin