Related papers: Running coupling effects for the singlet structure…
We report a semi-analytical approach for the solution of the nonlinear Gribov-Levin-Ryskin-Mueller-Qiu (GLR-MQ) evolution equation for sea quark distribution and investigate the effect of gluon shadowing on the small-x and moderate-Q^2…
We study the next-to-next-to-leading order (NNLO) evolution of flavour singlet parton densities and structure functions in massless perturbative QCD. Present information on the corresponding three-loop splitting functions is used to derive…
We derive a unitarity relationship between the spin structure function $g_{LT}(x,Q^{2})=g_{1}(x,Q^{2})+g_{2}(x,Q^{2})$, the LT interference diffractive structure function and the spin-flip coupling of the pomeron to nucleons. Our…
We present for the first time a self-contained calculation of the QCD running coupling at finite temperature and quark chemical potential, alpha_s(T, mu), based on a semiclassical background field method. The hard thermal/dense loop results…
We perform a global fit to the structure function F_2 measured in lepton-proton experiments at small values of Bjorken-x, x\le 0.01, for all experimentally available values of Q^2, 0.045 GeV^2\le Q^2 \le 800 GeV^2. We show that the recent…
The perturbative expression of the running strong coupling constant \alpha_{\rm s}(Q^{2}) has an unphysical singularity for Q^{2} = \Lambda^{2}_{\rm QCD}. Various modification have been proposed for the infrared region. The effect of some…
The perturbative QCD predicts that the growth of the gluon density at small-$x$ (high energies) should saturate, forming a Color Glass Condensate (CGC), which is described in mean field approximation by the Balitsky-Kovchegov (BK) equation.…
A finite-size scaling technique is applied to the SU(2) gauge theory (without matter fields) to compute a non-perturbatively defined running coupling alpha(q) for a range of momenta q given in units of the string tension K. We find that…
A main feature of high-energy scattering in QCD is saturation in the number density of gluons. This phenomenon is described by non-linear evolution equations, JIMWLK and BK, which have been derived at leading logarithmic accuracy. In this…
We discuss the effect of infrared soft gluons on the asymptotic behaviour of the total cross-section. We use a singular but integrable expression for the strong coupling constant in the infrared limit and relate its behaviour to the…
The perturbative QCD predictions for the small $x$ behaviour of the nucleon structure functions $F_{2,L}(x,Q^2)$ and $g_1(x,Q^2)$ are summarized. The importance of the double logarithmic terms for the small $x$ behaviour of the spin…
Predictions for the spin dependent structure function $g_1$ of the nucleon are presented. We use an unified approach incorporating the LO DGLAP evolution and the resummation of double logarithmic terms $ln^2(x)$. We show, that the singular…
The proton spin dependent structure function $g_1^p$ is analysed using the unified scheme incorporating both Altarelli-Parisi evolution and the double $ln^2(1/x)$ effects at low $x$. The latter are found to be very important in the region…
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…
Single particle inclusive energy spectra in $e^+e^-$ annihilation are analyzed in terms of moments. By assuming Local Parton Hadron Duality (LPHD), experimental data in a wide c.m. energy range from 3 GeV up to LEP energy are compared to…
Starting from the leading Odderon solution of the three gluon system in perturbative QCD we introduce, as a first step towards the transition to the nonperturbative region, an infrared cutoff and use the running QCD coupling constant. In…
The contributions to the deep inelastic scattering structure function which arise from emission of zero, one, two or three resolvable gluons and any number of unresolvable ones are computed to order ${\bar \alpha}_{S}^{3}$. Coherence…
We study the dependence of beta-function on running coupling constant in holographic models supported by Einstein-dilaton-Maxwell action for light and heavy quarks. Although, in the previous paper [arXiv:2402.14512], we considered different…
We present approximations of varying degree of sophistication to the integral equations for the (gluon) structure functions of a hadron (``the partonic flux factor'') in a model valid in the Leading Log Approximation with a running coupling…
The $\tau$ decay rate into hadrons of invariant mass smaller than $\sqrt{s_0}\gg\Lambda_{\rm QCD}$ can be calculated in QCD assuming global quark--hadron duality. It is shown that this assumption holds for $s_0>0.7$~GeV$^2$. From…