Related papers: Has HERA reached a new QCD regime?
HERA data on diffractive DIS show deviations from twist 2 DGLAP predictions below $Q^2\sim 5$ GeV$^2$ at low pomeron $\xi$, which may reach up to 100%. These deviations are consistent with higher twists effects extracted from the saturation…
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…
These notes are a summary of our predictions for the new THERA project, related to deep inelastic scattering in the region of ultra low $x$ ($x \to 10^{-7}$). We collect here predictions that satisfy two criteria (i) they do not depend on…
The parton momentum density distributions in the proton are determined from a next-to-leading order QCD analysis of structure functions measured at HERA and by fixed target experiments. Also included are data on the difference of the up and…
QCD predictions on the low-$x$ behaviour of the structure functions are reviewed and compared with the recent measurements of $F_2(x,Q^2)$ at HERA. The present theoretical accuracy of these predictions is discussed.
The HERA luminosity upgrade is expected to provide statistically significant measurements of the proton structure functions at 0.5<x<0.7 and very high Q2 (Q2>>M_{Z}^2). The behaviour of the parton densities (PDFs) in this high x, Q2 regime…
We analyse, within a dipole model, the inclusive DIS cross section data, obtained from the combination of the H1 and ZEUS HERA measurements. We show that these high precision data are very well described within the dipole model framework,…
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…
Calculations are presented of the longitudinal structure function $F_L(x, Q^2)$. We use next-to-leading order expressions in QCD $({\cal{O}}(\alpha_s^2))$ plus parton densities determined previously from global fits to data on deep…
A selection of theoretical and experimental results are presented in the broader context of understanding QCD and its relation to photon physics. A phenomenological analysis of HERA data to constrain the gluon content of the proton and…
Using the analytical expression for transverse momentum dependent (TMD) gluon density in a proton, a self-consistent simultaneous description of low $Q^2$ data on proton structure function $F_2(x,Q^2)$, reduced cross section for the…
Measurements of proton structure functions made in neutral and charged current interactions at HERA are discussed, covering four-momentum transfers Q^2 from about 0.5 GeV^2 to 30000 GeV^2. The results include the rise of the structure…
The parton momentum densities in the proton are obtained from a NLO QCD analysis of structure functions measured by HERA and fixed target experiments. The uncertainties in these parton densities, the structure functions and related cross…
New structure function measurements from fixed target experiments and especially HERA are reviewed. The extraction of parton distributions from these measurements is discussed with special emphasis on systematic problems. Finally the…
We present estimates of possible data on spin-dependent asymmetries in inclusive scattering of high energy polarized electrons by high energy polarized protons at HERA with their statistical errors and discuss systematic errors. We show…
The evidence from HERA for parton saturation, and other low-$x$ effects beyond the conventional DGLAP formalism, is recalled and critically reviewed in the light of new data and analyses presented at the conference.
Deep inelastic electron proton scattering at HERA II will allow precise studies of QCD and stringent tests of physics beyond the standard model. We discuss these two aspects of DIS with emphasis on the regime of high gluon densities at…
The results are presented of a study of the accuracy one may achieve at HERA in measuring the strong coupling constant $\alpha_s$ and the gluon distribution $xg(x,Q^{2})$ using future data of the structure function $F_{2}(x,Q^{2})$ which…
This talk covers three contributions from H1: "Measurement of the inclusive e^\pm p scattering cross section at high inelasticity y and of the structure function F_L", "Determination of the integrated luminosity at HERA using elastic QED…
We study infrared contributions to the QCD description of the HERA data on the structure function $F_{2}$ within the \textit{generalized} DAS approximation. We argue that this approximation is a natural one and consistent with the…