scholarly journals Next-to-next-to-leading order QCD analysis of spin-dependent parton distribution functions and their uncertainties: Jacobi polynomials approach

2016 ◽  
Vol 93 (11) ◽  
Author(s):  
F. Taghavi-Shahri ◽  
Hamzeh Khanpour ◽  
S. Atashbar Tehrani ◽  
Z. Alizadeh Yazdi
Keyword(s):  
Parton Distribution ◽  
Jacobi Polynomials ◽  
Distribution Functions ◽  
Leading Order ◽  
Parton Distribution Functions ◽  
Qcd Analysis

scholarly journals CAN POLARIZED DRELL-YAN SHED MORE LIGHT ON THE PROTON SPIN?

1992 ◽  
Vol 07 (29) ◽  
pp. 2695-2702 ◽  
Author(s):  
PRAKASH MATHEWS ◽  
V. RAVINDRAN
Keyword(s):  
Inelastic Scattering ◽  
Deep Inelastic Scattering ◽  
Parton Distribution ◽  
Factorization Method ◽  
Distribution Functions ◽  
Proton Spin ◽  
Leading Order ◽  
Parton Distribution Functions ◽  
First Moment ◽  
Polarized Deep Inelastic Scattering

We analyze polarized Drell-Yan process using the factorization method and derive operator definitions for polarized parton distribution functions. We demonstrate that a factorization analogous to that in the unpolarized Drell-Yan case holds in this process. We study the leading order gluonic contribution to the first moment of polarized Drell-Yan function and show that it is consistent with the results obtained from polarized deep inelastic scattering.

H1 INCLUSIVE CROSS-SECTION MEASUREMENTS AND AN EXTRACTION OF PARTON DISTRIBUTION FUNCTIONS

2005 ◽  
Vol 20 (21) ◽  
pp. 1557-1571
Author(s):  
BURKARD REISERT
Keyword(s):  
Cross Section ◽  
Parton Distribution ◽  
Inclusive Cross Section ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Single Experiment ◽  
Parton Distributions ◽  
The Standard Model ◽  
Qcd Analysis

An extraction of the parton distributions of the proton by a next-to-leading order QCD fit in the framework of the Standard Model is presented. The fit implements a novel decomposition of the quark species into up- and down-type quark distributions, which is the key to enable a determination of flavor separated parton distributions from a single experiment. The fit is performed on the inclusive unpolarized neutral and charged current cross-section measurements by the H1 collaboration at HERA. The discussion of uncertainties of parton distribution functions is based upon but extends the QCD analysis published together with the H1 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.

Transverse momentum dependent (TMD) parton distribution functions generated in the modified DGLAP formalism based on the valence-like distributions

2017 ◽  
Vol 32 (19n20) ◽  
pp. 1750121 ◽  
Author(s):  
H. Hosseinkhani ◽  
M. Modarres ◽  
N. Olanj
Keyword(s):  
Transverse Momentum ◽  
Parton Distribution ◽  
Dynamical Variable ◽  
Distribution Functions ◽  
Present Calculation ◽  
Leading Order ◽  
Parton Distribution Functions ◽  
Transverse Momentum Dependent ◽  
Longitudinal Structure Function ◽  
Wide Range

Transverse momentum dependent (TMD) parton distributions, also referred to as unintegrated parton distribution functions (UPDFs), are produced via the Kimber–Martin–Ryskin (KMR) prescription. The GJR08 set of parton distribution functions (PDFs) which are based on the valence-like distributions is used, at the leading order (LO) and the next-to-leading order (NLO) approximations, as inputs of the KMR formalism. The general and the relative behaviors of the generated TMD PDFs at LO and NLO and their ratios in a wide range of the transverse momentum values, i.e. [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] are investigated. It is shown that the properties of the parent valence-like PDFs are imprinted on the daughter TMD PDFs. Imposing the angular ordering constraint (AOC) leads to the dynamical variable limits on the integrals which in turn increase the contributions from the lower scales at lower [Formula: see text]. The results are compared with our previous studies based on the MSTW2008 input PDFs and it is shown that the present calculation gives flatter TMD PDFs. Finally, a comparison of longitudinal structure function [Formula: see text] is made by using the produced TMD PDFs and those that were generated through the MSTW2008-LO PDF from our previous work and the corresponding data from H1 and ZEUS collaborations and a reasonable agreement is found.

scholarly journals Polarized parton distribution functions: parametrization and transverse momentum dependence

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
H. Nematollahi ◽  
P. Abolhadi ◽  
S. Atashbar ◽  
A. Mirjalili ◽  
M. M. Yazdanpanah
Keyword(s):  
Data Analysis ◽  
Transverse Momentum ◽  
Parton Distribution ◽  
Jacobi Polynomials ◽  
Global Analysis ◽  
Distribution Functions ◽  
Momentum Dependence ◽  
Parton Distribution Functions ◽  
Transverse Momentum Dependent ◽  
Transverse Momentum Dependence

AbstractWe extract the polarized parton distribution functions (PPDFs) of proton. To this end we do a global analysis on recent and up-to-dated experimental data of polarized nucleon and deuteron structure functions at the NLO accuracy of perturbative QCD. We use the Jacobi polynomials expansion technique to do the required analyses. To achieve a more realistic estimation of the PPDFs and observable uncertainties we employ the Hessian error propagation. Following that we apply a theoretical approach which is based on imposing Lorentz structure in the parton model to investigate the transverse momentum dependence of these PPDFs. In this approach, the transverse momentum dependent (TMD) polarized parton distributions, which are also called the helicity distributions, are related to the integrated ones. This relation is indicating the priority and importance of data analysis for PPDFs. The results show a convenient general treatment expected for TMD densities which are in fact resulted from data analysis and fitting processes of integrated PPDFs in an adequate and a proper way.

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