scholarly journals Comment on “Parton Distributions,d/u, and Higher Twist Effects at Highx”

2000 ◽  
Vol 84 (23) ◽  
pp. 5455-5455 ◽  
Author(s):  
W. Melnitchouk ◽  
I. R. Afnan ◽  
F. Bissey ◽  
A. W. Thomas
Keyword(s):  
Higher Twist Effects ◽  
Parton Distributions

scholarly journals Parton Distributions,d/u, and Higher Twist Effects at Highx

1999 ◽  
Vol 82 (12) ◽  
pp. 2467-2470 ◽  
Author(s):  
U. K. Yang ◽  
A. Bodek
Keyword(s):  
Higher Twist Effects ◽  
Parton Distributions

scholarly journals Small x behavior of parton distributions: a study of higher twist effects

2008 ◽  
Vol 39 (3) ◽  
pp. 307-347 ◽  
Author(s):  
A. Yu. Illarionov ◽  
A. V. Kotikov ◽  
G. Parente
Keyword(s):  
Higher Twist Effects ◽  
Parton Distributions ◽  
Small X

scholarly journals Shadowing Aspects of Nuclear Parton Distributions

1997 ◽  
Vol 50 (1) ◽  
pp. 45
Author(s):  
S. Kumano
Keyword(s):  
Valence Quark ◽  
Parton Model ◽  
Symmetric Case ◽  
Dependent Data ◽  
Model Framework ◽  
Higher Twist Effects ◽  
Parton Distributions ◽  
Nuclear Dependence ◽  
Nuclear Interactions

Various shadowing aspects of nuclear parton distributions are discussed in a parton-model framework. We explain existing x dependent data of F2A /F2D, then the model is applied to a flavour asymmetry – d in a nucleus, to shadowing in valence-quark distributions, and to nuclear dependence of Q2 evolution. First, we find that a finite nuclear ū – đ distribution could be possible due to nuclear interactions even in the flavour symmetric case in the nucleon ( ū – đ = 0). Second, it is indicated that valence-quark shadowing could be used for discriminating among various shadowing models. Third, we find that nuclear dependence of Q2 evolution ∂ [F2Sn/F2C]/∂[ln Q2], which was found by the New Muon Collaboration (NMC), is essentially understood by modification of parton distributions in nuclei. However, higher-twist effects in nuclear interactions could be tested by studying the details of the nuclear Q2 evolution.

PARTON DISTRIBUTION FUNCTIONS AND THE QCD-IMPROVED PARTON MODEL — AN OVERVIEW

1987 ◽  
Vol 02 (04) ◽  
pp. 1369-1387 ◽  
Author(s):  
Wu-Ki Tung
Keyword(s):  
Parton Distribution ◽  
Particle Production ◽  
Heavy Particle ◽  
Parton Model ◽  
Distribution Functions ◽  
Collider Physics ◽  
Parton Distribution Functions ◽  
Parton Distributions ◽  
First Order ◽  
Small X

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.

scholarly journals Double parton distributions in the pion from lattice QCD

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Gunnar S. Bali ◽  
Luca Castagnini ◽  
Markus Diehl ◽  
Jonathan R. Gaunt ◽  
Benjamin Gläßle ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Lattice Qcd ◽  
Quark Mass ◽  
Matrix Elements ◽  
Parton Distributions ◽  
Almost All ◽  
The Relationship

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.

QUARK ORBITAL ANGULAR MOMENTUM AND GENERALIZED PARTON DISTRIBUTIONS

2003 ◽  
Vol 18 (08) ◽  
pp. 1303-1309 ◽  
Author(s):  
XIANGDONG JI
Keyword(s):  
Angular Momentum ◽  
Quantum Chromodynamics ◽  
Orbital Angular Momentum ◽  
Parton Distributions ◽  
Generalized Parton Distributions ◽  
Quark Orbital Angular Momentum

In this talk, I review the merit of introducing and measuring the quark orbital angular momentum contribution to the spin of the nucleon in the context of quantum chromodynamics.

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