Related papers: Evolution at small x
The DGLAP, BFKL, modified DGLAP and modified BFKL equations are constructed in a unified partonic framework. The antishadowing effect in the recombination process is emphasized, which leads to two different small $x$ behaviors of gluon…
We study the reactions $\gamma^*(Q^2)p\to\rho^0 p$ and $\gamma^*(Q^2)p\to\gamma^*(Q^2) p$ at large Q^2 and $W^2/Q^2$ and small momentum transfer, $\kappa^2_\perp$, to the nucleon where the pomeron exchange dominates. At large Q^2 the…
The hard pomeron component needed to reproduce small-x data seems to be present in elastic scattering at moderate energy. If this is the case, it is likely that the total cross section at the LHC will be appreciably larger than previously…
We investigate the Q^2 evolution of parton distributions at small x values, obtained in the case of flat initial conditions. The contributions of twist-two and (renormalon-type) higher-twist operators of the Wilson operator product…
We show that it is possible to use hard-Pomeron behavior to the gluon distribution and singlet structure function at low $x$. We derive a second-order independent differential equation for the gluon distribution and the singlet structure…
The behavior of the gluon distribution of the proton in the low-$x$, low-$Q^2$ domain of deep inelastic electron-proton scattering (DIS) is being investigated. By considering two-gluon exchange as the dominant interaction in the low-$x$,…
Applications of perturbative QCD to deeply virtual Compton scattering and hard exclusive meson electroproduction processes require a generalization of usual parton distributions for the case when long-distance information is accumulated in…
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…
Following the Good-and-Walker picture, hard diffraction in the high-energy/small-x limit of QCD can be described in terms of eigenstates of the scattering matrix off a Color Glass Condensate. From the CGC non-linear evolution equations, it…
We solve a unified integral equation to obtain the $x, Q_T$ and $Q$ dependence of the gluon distribution of a proton in the small $x$ regime; where $x$ and $Q_T$ are the longitudinal momentum fraction and the transverse momentum of the…
I discuss the theoretical status of the `soft' pomeron and its place in describing generic diffractive processes. The role of perturbative QCD (pQCD) corrections is considered, in particular in the context of quasi-elastic vector meson…
Measurements of the proton structure function F_2 for 0.11 < Q^2 < 20000 GeV^2 and 1.2 X 10^-5 < x < 0.65 from ZEUS 1994-1997 measurements are presented. From ZEUS 1994 and 1995 F_2 data the slopes d(F_2)/d(ln Q^2) at fixed x and d(ln…
An unknown small-x behavior of nucleon structure functions gives appreciable uncertainties to high-energy neutrino-nucleon cross-sections. We construct structure functions using at small x Regge inspired description by A. Donnachie and P.…
We study the nuclear shadowing effect in the context of Glauber-Gribov multiple-scattering model and perturbative QCD. We find that at small x, the $Q^2$ evolution of the shadowing is much slower than the DGLAP evolution, due to the…
We show how the sum of a hard singularity, $F_{2H}(x,Q^2_0)\sim x^{-\lambda}$ and a soft Pomeron $F_{2P}(x,Q^2_0)\sim Const.$ for the singlet piece of the structure function $F_{2S}=F_{2H}+F_{2P}$ for $Q_0^2\sim a few GeV^2$, plus a…
We investigate the evolution of parton densities at small values of the momentum fraction, x, by including resummed anomalous dimensions in the renormalization group equations. The resummation takes into account the leading-logarithmic…
A wide variety of experimental data in hadronic reactions are described in terms of the exchange of an object called the soft pomeron. It is nonperturbative in origin and is perhaps associated with glueballs. The HERA measurements of $\nu…
We review the perturbative evolution of the polarized structure functions g_1 and their associated parton distribution functions, with particular emphasis on the anomalous coupling of the first moment of the polarized gluon distribution. We…
We give a complete account of how soft gluon, massless quark, evolution equations in colour space originate, from a factorization into a hard cross section density operator and a soft function encoding measurements and the projection on…
We examine the $Q^2$ evolution of gluon polarization in polarized nucleons. As is well known, the evolution of $\alpha_s \Delta G(Q^2)$ is negligible for typical momentum transfer variations found in experimental deep inelastic scattering.…