Structure functions and parton distributions

A comparative study of the most popular parton parametrizations is presented. The individual parton distributions as well as the F2 structure function are discussed with a particular emphasis on the low x region, 10−4<x<10−2. The predictions of these parametrizations for the F2 structure function have a wide spread which persists also in the HERA kinematical region.

Download Full-text

NUCLEAR SHADOWING EFFECTS ON CHARMONIUM PRODUCTION IN QCD

Modern Physics Letters A ◽

10.1142/s0217732398000528 ◽

1998 ◽

Vol 13 (06) ◽

pp. 453-463 ◽

Cited By ~ 3

Author(s):

C. PAJARES ◽

C. A. SALGADO ◽

Yu. M. SHABELSKI

Keyword(s):

Experimental Data ◽

Structure Functions ◽

Nuclear Medium ◽

Color Singlet ◽

Separate Study ◽

Factorization Approach ◽

Parton Distributions ◽

Charmonium Production ◽

Evaporation Model ◽

Nonrelativistic Qcd

It is shown that the effects on charmonium production of the modification of nucleon parton distributions inside nuclei are similar in the factorization approach based on nonrelativistic QCD and in the color evaporation model. In the first model, a separate study of the color octet and color singlet contributions to the yields of the various charmonium states as well as the contributions of these states to the total J/ψ production is performed. It is found that a clear xF dependence of these contributions which, together with an overall normalization given by absorption of the pre-resonant [Formula: see text] state inside the nuclear medium, can reproduce experimental data a for moderate xF. However, at large xF, there is bigger suppression that cannot be fit by this overall normalization together with the shadowing of structure functions.

Download Full-text

QCD ANALYSIS OF DEEP INELASTIC LEPTON-NUCLEON SCATTERING DATA

Modern Physics Letters A ◽

10.1142/s021773239200207x ◽

1992 ◽

Vol 07 (25) ◽

pp. 2307-2315

Author(s):

S. I. BILENKAYA ◽

D. B. STAMENOV

Keyword(s):

Cross Section ◽

Scale Parameter ◽

Structure Functions ◽

Mass Scale ◽

Scattering Data ◽

Nucleon Structure ◽

Leading Order ◽

Parton Distributions ◽

Qcd Analysis ◽

Good Agreement

A combined next-to-leading order QCD analysis of BCDMS µ H 2 ( D 2) and CDHS [Formula: see text] scattering data is presented. The nucleon structure functions are given in terms of parton distributions. Unlike most of the papers on this subject, the cross-section scattering data (not the values for the nucleon structure functions extracted from these data by additional extrapolations and assumptions) are fitted. A very good agreement of the data with the predictions of QCD for the parton distributions is observed. The QCD mass scale parameter Λ is determined from these data both in a flavor nonsinglet approximation and with a complete flavor singlet and non-singlet treatment. These two fits to the data give consistent results for Λ.

Download Full-text

ONCE MORE ON THE RADIATIVE CORRECTIONS TO THE NUCLEON STRUCTURE FUNCTIONS IN QCD

Modern Physics Letters A ◽

10.1142/s0217732395002180 ◽

1995 ◽

Vol 10 (27) ◽

pp. 2029-2039 ◽

Cited By ~ 1

Author(s):

D.B. STAMENOV

Keyword(s):

Structure Functions ◽

Nucleon Structure ◽

Radiative Corrections ◽

Parton Distributions ◽

Logarithmic Approximation

A new representation of the next-to-leading QCD corrections to the nucleon structure functions is given in terms of parton distributions. All O(αs) corrections to the leading logarithmic approximation (LLA) are included. In contrast to the similar representations in the literature terms of order [Formula: see text] do not appear in our expressions for the nucleon structure functions taken in the next-to-leading logarithmic approximation. This result is generalized for any order in αs beyond the LLA. Terms of order [Formula: see text] which belong only to the approximation considered are present in such a representation for the structure functions.

Download Full-text