scholarly journals THE SMALL x BEHAVIOR OF THE GLUON STRUCTURE FUNCTION FROM TOTAL CROSS-SECTIONS

2008 ◽  
Vol 23 (01) ◽  
pp. 151-165 ◽  
Author(s):  
E. G. S. LUNA ◽  
A. A. NATALE ◽  
C. M. ZANETTI
Keyword(s):  
Distribution Function ◽  
Cross Sections ◽  
Gluon Distribution ◽  
Mass Scale ◽  
Total Cross Sections ◽  
Gluon Distribution Function ◽  
Eikonal Model ◽  
Gluon Mass ◽  
Small X ◽  
Gluon Distributions

Within a QCD-based eikonal model with a dynamical infrared gluon mass scale we discuss how the small x behavior of the gluon distribution function at moderate Q2 is directly related to the rise of total hadronic cross-sections. In this model the rise of total cross-sections is driven by gluon–gluon semihard scattering processes, where the behavior of the small x gluon distribution function exhibits the power law xg(x, Q2) = h(Q2)x-∊. Assuming that the Q2 scale is proportional to the dynamical gluon mass one, we show that the values of h(Q2) obtained in this model are compatible with an earlier result based on a specific nonperturbative Pomeron model. We discuss the implications of this picture for the behavior of input valence-like gluon distributions at low resolution scales.

MODEL INDEPENDENT CONSTRAINT ON THE GLUON DISTRIBUTION FUNCTION G(X, Q2) AT SMALL X

1989 ◽  
Vol 04 (17) ◽  
pp. 1653-1665
Author(s):  
B.P. MAHAPATRA
Keyword(s):  
Distribution Function ◽  
Gluon Distribution ◽  
Hadron Colliders ◽  
Neutrino Scattering ◽  
Gluon Distribution Function ◽  
Small X ◽  
Model Independent ◽  
Near Future ◽  
First Time ◽  
Quark Flavors

An asymptotic constraint on the gluon distribution function G(x, Q2) for large Q2 and small x (→0), is derived in QCD, given by [Formula: see text] where Nf=number of quark flavors and [Formula: see text] is the standard structure function measured in deep inelastic neutrino scattering. It is shown that this constraint is a rigoros upper bound for xG at any finite — Q2 for small x→0 and hence can be used to check the self-consistency of different models for G(x, Q2) proposed to describe small x physics. The subasymptotic Q2-corections to the above relation is found to be small (~15–20%) in the kinematical domain of interest at the forthcoming hadron colliders, i.e., for x<10−2, Q2>103 GeV 2. The finite Q2 — corrections are again predominantly determined by [Formula: see text]. This may, for the first time, provide a method for direct experimental measurement of xG in near future, at HERA and TEVATRON.

scholarly journals HEAVY QUARK PHOTOPRODUCTION IN THE SEMIHARD APPROACH AT HERA AND BEYOND

1996 ◽  
Vol 11 (01) ◽  
pp. 25-35 ◽  
Author(s):  
V.A. SALEEV ◽  
N.P. ZOTOV
Keyword(s):  
Experimental Data ◽  
Heavy Quark ◽  
Cross Section ◽  
Cross Sections ◽  
Gluon Distribution ◽  
Longitudinal Polarization ◽  
Factorization Approach ◽  
Total Cross Sections ◽  
Small X ◽  
Saturation Effects

Processes of heavy quark photoproduction at HERA energies and beyond are investigated using the semihard (k⊥ factorization) approach. Virtuality and longitudinal polarization of gluons in the photon-gluon subprocess as well as the saturation effects in the gluon distribution function at small x have been taken into account. The total cross-sections, rapidity and p⊥ distributions of the charm and beauty quark photoproduction have been calculated. The results are compared with ZEUS experimental data for charm photoproduction cross-section.

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