scholarly journals Twist-2 relation and sum rule for tensor-polarized parton distribution functions of spin-1 hadrons

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
S. Kumano ◽  
Qin-Tao Song
Keyword(s):  
Parton Distribution ◽  
Spin Structure ◽  
Sum Rules ◽  
Parton Model ◽  
Structure Functions ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Higher Twist Effects ◽  
Sum Rule ◽  
Near Future

Abstract Sum rules for structure functions and their twist-2 relations have important roles in constraining their magnitudes and x dependencies and in studying higher-twist effects. The Wandzura-Wilczek (WW) relation and the Burkhardt-Cottingham (BC) sum rule are such examples for the polarized structure functions g1 and g2. Recently, new twist-3 and twist-4 parton distribution functions were proposed for spin-1 hadrons, so that it became possible to investigate spin-1 structure functions including higher-twist ones. We show in this work that an analogous twist-2 relation and a sum rule exist for the tensor-polarized parton distribution functions f1LL and fLT, where f1LL is a twist-2 function and fLT is a twist-3 one. Namely, the twist-2 part of fLT is expressed by an integral of f1LL (or b1) and the integral of the function f2LT = (2/3)fLT− f1LL over x vanishes. If the parton-model sum rule for f1LL (b1) is applied by assuming vanishing tensor-polarized antiquark distributions, another sum rule also exists for fLT itself. These relations should be valuable for studying tensor-polarized distribution functions of spin-1 hadrons and for separating twist-2 components from higher-twist terms, as the WW relation and BC sum rule have been used for investigating x dependence and higher-twist effects in g2. In deriving these relations, we indicate that four twist-3 multiparton distribution functions FLT, GLT, $$ {H}_{LL}^{\perp } $$ H LL ⊥ , and HTT exist for tensor-polarized spin-1 hadrons. These multiparton distribution functions are also interesting to probe multiparton correlations in spin-1 hadrons. In the near future, we expect that physics of spin-1 hadrons will become a popular topic, since there are experimental projects to investigate spin structure of the spin-1 deuteron at the Jefferson Laboratory, the Fermilab, the nuclotron-based ion collider facility, the electron-ion colliders in US and China in 2020’s and 2030’s.

scholarly journals POLARIZED STRUCTURE FUNCTIONS AND SPIN PHYSICS

2002 ◽  
Vol 17 (23) ◽  
pp. 3220-3238
Author(s):  
UTA STÖSSLEIN
Keyword(s):  
Parton Distribution ◽  
Spin Structure ◽  
High Energy ◽  
Structure Functions ◽  
Distribution Functions ◽  
High Energy Particle ◽  
Particle Interactions ◽  
Parton Distribution Functions ◽  
Spin Physics ◽  
Further Development

Recent progress in the field of spin physics of high energy particle interactions is reviewed with particular emphasis on the spin structure functions as measured in polarized deep inelastic lepton-nucleon scattering (DIS). New measurements are presented to obtain more direct information on the composition of the nucleon angular momentum, with results from semi-inclusive DIS accessing flavour-separated parton distribution functions (PDF) and with first data from hard exclusive reactions which may be interpreted in terms of recently developed generalizations of parton distribution functions (GPD). Finally, experimental prospects are outlined which will lead to a further development of the virtues of QCD phenomenology of the spin structure of the nucleon.

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 LORENTZ INVARIANCE RELATIONS AND WANDZURA–WILCZEK APPROXIMATION

2009 ◽  
Vol 24 (35n37) ◽  
pp. 2950-2959 ◽  
Author(s):  
T. TECKENTRUP ◽  
A. METZ ◽  
P. SCHWEITZER
Keyword(s):  
Parton Distribution ◽  
Lorentz Invariance ◽  
Distribution Functions ◽  
Complete List ◽  
Parton Distribution Functions ◽  
Sum Rule ◽  
Model Independent

A complete list of the so-called Lorentz invariance relations between parton distribution functions is given and some of their consequences are discussed, such as the Burkhardt-Cottingham sum rule. The violation of these relations is considered in a model independent way. It is shown that several Lorentz invariance relations are not violated in a generalized Wandzura–Wilczek approximation, indicating that numerically their violation may be small.

scholarly journals NUCLEAR PARTON DENSITIES AND STRUCTURE FUNCTIONS

2005 ◽  
Vol 20 (08n09) ◽  
pp. 1927-1930 ◽  
Author(s):  
S. ATASHBAR TEHRANI ◽  
ALI N. KHORRAMIAN ◽  
A. MIRJALILI
Keyword(s):  
Experimental Data ◽  
Structure Function ◽  
Nuclear Structure ◽  
Parton Distribution ◽  
Constituent Quark ◽  
Structure Functions ◽  
Constituent Quark Model ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Good Agreement

We calculate nuclear parton distribution functions (PDFs), using the constituent quark model. We find the bounded valon distributions in a nuclear to be related to free valon distributions in a nucleon. By using improved bounded valon distributions for a nuclear with atomic number A and the partonic structure functions inside the valon, we can calculate the nuclear structure function in x space. The results for nuclear structure-function ratio [Formula: see text] at some values of A, are in good agreement with the experimental data.

scholarly journals An analysis of parton distribution functions of the pion and the kaon with the maximum entropy input

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Chengdong Han ◽  
Gang Xie ◽  
Rong Wang ◽  
Xurong Chen
Keyword(s):  
Parton Distribution ◽  
Valence Quark ◽  
Quark Distribution ◽  
Parton Model ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Theoretical Predictions ◽  
Gluon Distributions ◽  
Qcd Analysis ◽  
Mass Dependent

AbstractWe present pion and kaon parton distribution functions from a global QCD analysis of the experimental data within the framework of dynamical parton model. We use the DGLAP equations with parton–parton recombination corrections and the valence input of uniform distribution which maximizes the information entropy. At our input scale $$Q_0^2$$ Q 0 2 , there are no sea quark and gluon distributions. All the sea quarks and gluons of the pion and the kaon are completely generated from the parton splitting processes. The mass-dependent parton splitting kernel is applied for the strange quark distribution in the kaon. The obtained valence quark and sea quark distributions at high $$Q^{2}$$ Q 2 ($$Q^2>5$$ Q 2 > 5 GeV$$^2$$ 2 ) are compatible with the existed experimental measurements. Furthermore, the asymptotic behaviours of parton distribution functions at small and large x have been studied for both the pion and the kaon. Lastly, the first three moments of parton distributions at high $$Q^{2}$$ Q 2 scale are calculated, which are consistent with other theoretical predictions.

scholarly journals SPIN STRUCTURE FUNCTIONS AND INTRINSIC MOTION OF THE CONSTITUENTS

2003 ◽  
Vol 18 (08) ◽  
pp. 1397-1402
Author(s):  
PETR ZÁVADA
Keyword(s):  
Spin Structure ◽  
Rest Frame ◽  
Mass Shell ◽  
Sum Rules ◽  
Parton Model ◽  
Structure Functions ◽  
Quark Parton Model ◽  
Intrinsic Motion ◽  
Spin Structure Functions ◽  
The Moment

The spin structure functions of the system of quasifree fermions on mass shell are studied in a consistently covariant approach. Comparison with the basic formulas following from the quark-parton model reveals the importance of the fermion motion inside the target for the correct evaluation of the spin structure functions. In particular it is shown, that regarding the moment Γ1, both the approaches are equivalent for the static fermions, but differ by the factor 1/3 in the limit of massles fermions (m ≪ p0, in target rest frame). Some other sum rules are discussed as well.

scholarly journals Higher Twist Structure Functions

1997 ◽  
Vol 50 (1) ◽  
pp. 61 ◽  
Author(s):  
A. I. Signal
Keyword(s):  
Parton Distribution ◽  
Structure Functions ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Bag Model ◽  
Mit Bag Model ◽  
Twist Structure

I discuss the importance of some of the higher twist structure functions, and then calculate the twist-two, three and four parton distribution functions involving two quark unpolarized correlations using the wavefunction of the MIT bag model.

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