Scaling violation and shadowing corrections at HERA

Abstract

We study the value of shadowing corrections (SC) in the HERA kinematic region in the Glauber-Mueller approach. Since the Glauber-Mueller approach was proven in perturbative quantum chromodynamics (QCD) in the double-logarithmic approximation (DLA), we develop the DLA approach for the deep inelastic structure function which takes into account the SC. Our estimates show small SC for F2 in the HERA kinematic region while they turn out to be sizable for the gluon structure function. We compare our estimates with those for gluon distribution in leading order (LO) and next to leading order (NLO) in the DGLAP evolution equations.

New possibilities of old soft pomeron in DIS

“…The parameters must obey some restrictions to avoid unphysical situations (for example, the cross-section might become negative if we do not constrain d 2∞ ≥ d 1∞ ). These restrictions were taken into account when fitting (6)(7)(8)(9)(10)(11)(12)(13) to the available experimental data.…”

“…2.2 (γ, p) cross-section (at Q 2 = 0). In the DP model, from (5)(6)(7)(8)(9)(10)(11)(12)(13)(14) we obtain…”

“…iii) What do we know about unitarity in lepton-hadron Deep Inelastic Scattering (DIS)? How important are the shadowing corrections (SC) to the hard pomeron at small values of x [4,5,8,9] ? Does the Froissart-Martin bound for hadronic total cross-sections remain valid for γp-interaction?…”

“…III) Quantitative estimates of unitarity, shadowing corrections to structure functions as well as to parton distribution functions depend on additional assumptions within a specified procedure of unitarization. However, numerical estimates of SC originated from short distances show [8,13] that these effects are not small though they do not change qualitatively the behaviour of structure functions at least at moderate Q 2 and when x ∼ < 10 −2 . As for the unitarity condition in DIS, there is a common belief that the Froissart-Martin bound can not be proved for a process including "external" offmass-shell particles.…”

A phenomenological analysis of the longitudinal structure function at small x and low Q 2

“…Therefore, new dynamical non-linear QCD effects associated to the unitarity corrections are expected to slow down its further growth [1,2,3,4,5,6,7]. The search of signatures for these effects has been an active subject of research in the last years [8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24].…”