scholarly journals Polarized parton distributions in perturbative QCD

2000 ◽  
Vol 666-667 ◽  
pp. 278-281 ◽  
Author(s):  
G. Ridolfi
2015 ◽  
Vol 37 ◽  
pp. 1560037 ◽  
Author(s):  
Koichi Kanazawa ◽  
Cedric Lorcé ◽  
Andreas Metz ◽  
Barbara Pasquini ◽  
Marc Schlegel

Generalized transverse-momentum dependent parton distributions (GTMDs) encode the most general parton structure of hadrons. In this contribution, which is largely based on a recent publication,1 we focus on two twist-2 GTMDs which are denoted by F1,4 and G1,1 in parts of the literature. As already shown previously, both GTMDs have a close relation to orbital angular momentum of partons inside a hadron. However, recently even the mere existence of F1,4 and G1,1 has been doubted. We explain why this claim does not hold. We support our model-independent considerations by calculating the GTMDs in two spectator models and in perturbative QCD. For the model results we also explicitly check the relation to the orbital angular momentum of partons inside hadrons.


1989 ◽  
Vol 04 (13) ◽  
pp. 1257-1276 ◽  
Author(s):  
G.P. KORCHEMSKY

The asymptotics of the evolution kernels Pab(z) of parton distributions is investigated as z→1. It is proven that to all orders of perturbative QCD, [Formula: see text] where [Formula: see text] is the cusp anomalous dimension of the contour functionals in the fundamental (α=“quark”) and adjoint (α=“gluon”) representations of gauge group and, to the lowest orders, Cα are related to the anomalous dimension of a quark field in the axial gauge and the beta function of QCD by a simple equation.


2004 ◽  
Vol 19 (07) ◽  
pp. 1074-1088 ◽  
Author(s):  
R. S. THORNE

I discuss our current understanding of parton distributions. I begin with the underlying theoretical framework, and the way in which different data sets constrain different partons, highlighting recent developments. The methods of examining the uncertainties on the distributions and those physical quantities dependent on them is analyzed. Finally I look at the evidence that additional theoretical corrections beyond NLO perturbative QCD may be necessary, what type of corrections are indicated and the impact these may have on the uncertainties.


1994 ◽  
Vol 09 (09) ◽  
pp. 849-852 ◽  
Author(s):  
C. J. BENESH

A simple, new method for solving the Q2 evolution of parton distributions in perturbative QCD using cubic splines is described and applied to the evolution of non-singlet quark distributions.


2003 ◽  
Vol 12 (02) ◽  
pp. 177-195
Author(s):  
K. J. Eskola ◽  
H. Honkanen ◽  
V. J. Kolhinen ◽  
P. V. Ruuskanen ◽  
C. A. Salgado

Determination of the nuclear parton distributions within the framework of perturbative QCD, the DGLAP equations in particulars, is discussed. Scale and flavour dependent nuclear effects in the parton distributions are compared with the scale and flavour independent parametrizations of HIJING and of the Hard Probe Collaboration. A comparison with the data from deep inelastic lepton-nucleus scattering and the Drell–Yan process in proton-nucleus collisions is shown.


2005 ◽  
Vol 44 (1) ◽  
pp. 69-85 ◽  
Author(s):  
A. D. Martin ◽  
M. G. Ryskin ◽  
G. Watt

1987 ◽  
Vol 02 (04) ◽  
pp. 1369-1387 ◽  
Author(s):  
Wu-Ki Tung

Some non-trivial features of the QCD-improved parton model relevant to applications on heavy particle production and semi-hard (small-x) processes of interest to collider physics are reviewed. The underlying ideas are illustrated by a simple example. Limitations of the naive parton formula as well as first order corrections and subtractions to it are dis-cussed in a quantitative way. The behavior of parton distribution functions at small x and for heavy quarks are discussed. Recent work on possible impact of unconventional small-x behavior of the parton distributions on small-x physics at SSC and Tevatron are summarized. The Drell-Yan process is found to be particularly sensitive to the small x dependence of parton distributions. Measurements of this process at the Tevatron can provide powerful constraints on the expected rates of semi-hard processes at the SSC.


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Gunnar S. Bali ◽  
Luca Castagnini ◽  
Markus Diehl ◽  
Jonathan R. Gaunt ◽  
Benjamin Gläßle ◽  
...  

Abstract We perform a lattice study of double parton distributions in the pion, using the relationship between their Mellin moments and pion matrix elements of two local currents. A good statistical signal is obtained for almost all relevant Wick contractions. We investigate correlations in the spatial distribution of two partons in the pion, as well as correlations involving the parton polarisation. The patterns we observe depend significantly on the quark mass. We investigate the assumption that double parton distributions approximately factorise into a convolution of single parton distributions.


Sign in / Sign up

Export Citation Format

Share Document