Related papers: HERA data and DGLAP evolution: theory and phenomen…
This talk is a rather sceptical review of our knowledge and understanding of deep inelastic scattering at low x (high energy). We show that the well known success of the DGLAP evolution equations in describing of experimental HERA data…
We investigate the Q^2 evolution of parton distributions at small x values, recently obtained in the case of soft initial conditions. The results are in excellent agreement with deep inelastic scattering experimental data from HERA.
In the leading twist approximation of the Wilson operator product expansion with "frozen" and analytic strong coupling constants we show that Bessel-inspired behavior of the structure function F2 at small x, obtained for a flat initial…
We investigate the Q^2 evolution of parton distributions at small x values, obtained in the case of flat initial conditions. The results are in excellent agreement with deep inelastic scattering experimental data from HERA.
We provide an assessment of the impact of parton distributions on the determination of LHC processes, and of the accuracy with which parton distributions (PDFs) can be extracted from data, in particular from current and forthcoming HERA…
We review recent HERA data on the structure function F_2 at small x and large Q^2. We show that the salient features of the data are revealed by comparing them to the double asymptotic scaling behaviour which F_2 is predicted to satisfy in…
Small-$x$ logarithmic enhancements arising from high-energy gluon emissions affect both the evolution of collinearly-factorized parton densities and partonic coefficient functions. With the higher collider energy reached by the LHC, the…
It has been observed recently that a consistent LO BFKL gluon evolution leads to a steep growth of F_2(x,Q^2) for x -> 0 almost independently of Q^2. We show that current data from the DESY HERA collider are precise enough to finally rule…
We study the perturbative QCD corrections to heavy-quark structure functions of charged-lepton deep-inelastic scattering and their impact on global fits of parton distributions. We include the logarithmically enhanced terms near threshold…
We determine diffractive parton distributions of the proton from DGLAP based fits to HERA data including the twist--4 contribution from longitudinal polarized virtual photons, which is known to be important in the region of large beta. The…
It is shown that in the leading twist approximation of the Wilson operator product expansion with "frozen" and analytic strong coupling constants, considering the Bessel-inspired behavior of the structure functions F2 and the derivative d…
An approach which unifies the Double Logarithmic Approximation at small x and the leading order DGLAP evolution of fragmentation functions at large x is presented. This approach reproduces exactly the Modified Leading Logarithm…
Forward jet and multijet production has been measured at low Bjorken x at HERA. The measured cross sections and correlations were compared to predictions from DGLAP-based fixed-order calculations. Further comparisons were made to…
It has been found that recent results on forward jet production from deep inelastic scattering can neither be reproduced by models which are based on leading order alpha_s QCD matrix elements and parton showers nor by next-to-leading order…
The measurement of forward jet cross sections has been suggested as a promising probe of new small x parton dynamics and the question is whether the new HERA data provide an indication of this. In this paper the influence of resolved photon…
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…
We examine the latest HERA experimental measurements of the $Q^2$ logarithmic derivative of the proton structure function. We analyze the characteristics of DGLAP with and without screening, as well as a Regge type model, and compare their…
We study the perturbative QCD description of the HERA measurements of $F_2 (x, Q^2)$ using a gluon distribution that is obtained from an evolution incorporating angular ordering of the gluon emissions, and which embodies both GLAP and BFKL…
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…
We present particular and unique solutions of singlet and non-singlet Dokshitzer-Gribov-Lipatov- Altarelli-Parisi (DGLAP) evolution equations in next-to-next-to-leading order (NNLO) at low-x. We obtain t-evolutions of deuteron, proton,…