Related papers: Structure functions and low x physics
We analyse the data for the proton structure function $F_2$ over the entire $Q^2$ domain, including especially low $Q^2$, in terms of perturbative and non-perturbative QCD contributions. The small distance configurations are given by…
Inclusive and diffractive structure functions for electron-proton scattering are calculated in a semiclassical approach at large momentum transfer $Q^2$ and small values of the scaling variable $x$. The basic process is the production of a…
The scale dependence of the evolution of photoproduction cross sections with the photon-proton centre of mass energy W is studied using low Q^2 < 0.01 GeV^2 e^+p interactions collected by the H1 experiment at HERA. The value of the largest…
Structure functions are a measure of the partonic structure of hadrons, which is important for any process which involves colliding hadrons. They are a key ingredient for deriving partons distributions in nucleons. In recent years dramatic…
We present our analysis on the photon structure functions at small Bjorken variable x in the framework of the holographic QCD. In the kinematic region, a photon can fluctuate into vector mesons and behaves like a hadron rather than a…
We present a set of formulas to extract the ratio $F_{L}(x,Q^{2})/F_{2}(x,Q^{2})$ and $R(x,Q^{2})$ from the proton structure function parameterized in the next-to-next-to-leading order of the perturbative theory at low $x$ values. The…
At HERA, the electron-proton collider at DESY, Hamburg, the large flux of almost on-shell photons accompanying the lepton beam is being used to shed new light on the structure of the photon. Recent results are reviewed and discussed, with…
The photoproduction of Drell-Yan lepton pairs at HERA is studied. We show that in the backward rapidity region the cross section is strongly sensitive to the small-$x$ behaviour of the quark distributions in the proton, and that with…
This talk reviews the latest measurements of the proton, Pomeron and photon structure functions. These measurements, especially at low $x$ and/or low $Q^2$ lead to new insight into the picture of hadronic interactions.
New structure function results from H1 are presented. The measurements cover a huge kinematical range for Q^2, the four momentum transfer squared, from 0.35, GeV^2 to 30,000, GeV^2, and for Bjorken x between \sim 5\cdot 10^{-6} and 0.65. At…
We present a summary of the physics of gluon saturation and non-linear QCD evolution at small values of parton momentum fraction $x$ in the proton and nucleus in the context of recent experimental results at HERA and RHIC. The rich physics…
The kinematic region covered by the LHC experiments probes low values of Bjorken-$x$. At the scale relevant for $W$ and $Z$ production the central rapidity region covers $10^{-3} < x < 10^{-1}$. This means that it is the HERA data which…
The latest structure function results, as presented at the ICHEP98 conference, are reviewed. A brief introduction to the formalism and the status of global analyses of parton distributions is given. The review focuses on three experimental…
Deep-inelastic scattering at small x is a new field of QCD phenomenology which HERA experiments started to explore. The data show the feature expected by the perturbative Regge asymptotics. We describe the parton picture of structure…
It is shown that recent small-x measurements of the photon structure function F_2^{\gamma}(x,Q^2) by the LEP-OPAL collaboration are consistent with parameter-free QCD predictions at all presently accessible values of Q^2.
In the early eighties, L\'opez, Gonz\'alez-Arroyo and the present author proved that, if at a given $Q_0^2$ large enough for perturbative QCD to be valid, structure functions behave as a power of $x$ for $x\rightarrow 0$, then for all…
The QCD structure of the electron is defined and calculated. The leading order splitting functions are extracted, showing an important contribution from $\gamma$-$Z$ interference. Leading logarithmic QCD evolution equations are constructed…
The measurement and QCD analysis of neutral and charged current cross sections at HERA are presented. For the kinematic range of four-momentum transfer Q^2 between approx. 1 GeV^2 and 30000 GeV^2 and Bjorken x between 0.0013 and 0.65 the…
A multidimensional extraction of the structure function ratio $\sigma_{LT'}/\sigma_{0}$ from the hard exclusive $\vec{e} p \to e^\prime n \pi^+$ reaction above the resonance region has been performed. The study was done based on beam-spin…
The operation of HERA with polarized proton and electron beams will allow to study a wide variety of observables in polarized electron-proton collisions at $\sqrt s=300$ GeV. The physics prospects of this project have been elaborated in…