Related papers: Singlet structure function g_1 at small x and smal…

We discuss the angular dependence of the recently proposed transverse momentum dependent quark and gluon diffractive parton distributions at small-$x$. We introduce the difractive versions of the Sivers function and the elliptic gluon…

We present an update of a phenomenological model for the spin dependent structure functions $g_1(x,Q^2)$ of the proton and neutron. This model is based on a broken SU(6) wavefunction parametrized by the unpolarized structure functions. The…

The interpretation of virtual gluons as ghosts in the non-linear gluonic structure of QCD permits the formulation and realization of a manifestly gauge-invariant and Lorentz covariant theory of interacting quarks/anti-quarks, for all values…

We study the chiral-odd transversity spin-dependent quark distribution function $h_1 (x)$ of the nucleon in a constituent quark model. The twist-2 structure functions, $f_1(x)$, $g_1(x)$ and $h_1(x)$ are calculated within the diquark…

We derive relations between spin-dependent nuclear and nucleon g_1 and g_2 structure functions within the nuclear impulse approximation, which are valid at all Q^2, and in both the resonance and deep inelastic regions. We apply the…

The implications of the positivity constraint on the presently unknown polarized structure function of the photon, $g_1^{\gamma}(x,Q^2)$, are studied in detail. In particular the non-trivial consequences of this constraint,…

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…

Theoretical predictions show that at low values of Bjorken $x$ the spin structure function, $g_1$ is influenced by large logarithmic corrections, $ln^2(1/x)$, which may be predominant in this region. These corrections are also partially…

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…

Recent data on the structure function F_2(x,Q^2) at small values of x are analysed and compared with theoretical expectations. It is shown that the observed rise at small x is consistent with a logarithmic increase, growing logarithmically…

Infrared evolution equations for small-$x$ behaviour of the non-singlet structure functions $f_1^{NS}$ and $g_1^{NS}$ are obtained and solved in the next-to-leading approximation, to all orders in $\alpha_s$, and including running…

We consider in detail the Q^2 -dependence of the DIS structure functions, with Q being the virtual photon momentum. Quite often this dependence is claimed to be originated by the Q^2-dependence of the QCD coupling. This leads to the small-x…

Equation for the sum of BFKL pomeron fan diagrams is rederived by direct summation and solved numerically for rapidities $y\leq 50$. At high rapidities y>20 the resulting cross-sections for the scattering of a longitudinally polarized…

We show that if the Lorentz transformation properties of diffraction are other than scalar, the $x \rightarrow 0$ behaviour of $g_1(x,Q^2)$ can grow. We compare with new data on $g_1^p$ from SMC, assess implications for sum rules and for…

We propose a modified Balitsky-Fadin-Kuraev-Lipatov equation from the viewpoint of the resummation technique, which contains an intrinsic dependence on momentum transfer Q, and satisfies the unitarity bound. The idea is to relax the strong…

We obtain a pair of second order differential equations in two variables $x$ and $t$ from the coupled DGLAP QCD evolution equations at small $x$ using the standard Taylor series expansion method.To that end we keep terms upto $O(x^2 )$.We…

The $t$-dependence and the $(M_x^2/s)$-dependence of the double differential cross-sections for inelastic diffractive scattering off proton-target are discussed. Here $t$ stands for the four-momentum-transfer squared, $M_x$ for the missing…

We present a study of the contribution of antishadowing effects on the gluon distribution functions $G(x,Q^2)$ in light of the Gribov-Levin-Ryskin-Mueller-Qiu, Zhu-Ruan-Shen (GLR-MQ-ZRS) nonlinear equation at small-$x$, where $x$ is 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, including statistical errors, and discuss systematic uncertainties. We…

We give predictions for the ratio RQ(x,Q2)=FLQ(x,Q2)/F2Q(x,Q2) at small values of Bjorken variable x in the first three orders of perturbation theory. We show an approximate x-independence of RQ(x,Q2) at low x and non-large Q2 values (Q2 <…