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Uncertainty of parton distribution functions due to physical observables in a global analysis

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Chinese Physics C 2017年第2期41卷 41-49页

作者： Alireza Aleedaneshvar Muhammad Goharipour Saeedeh Rostami Physics Department 35131-19111 Semnan University Semnan Iran

The recent measurement of the differential γ ＋ c-jet cross section, performed at the Tevatron collider in Run II by the D0 collaboration, is studied in a next-to-leading order（NLO） global QCD analysis to assess its impact on the proton parton distribution functions（PDFs）. We show that these data lead to a significant change in the gluon and charm quark distributions. We demonstrate also that there is an inconsistency between the new high precision HERA I＋II combined data and Tevatron measurement. Moreover, in this study we investigate the impact of older EMC measurements of charm structure function F_c^2 on the PDFs and compare the results with those from the analysis of Tevatron data. We show that both of them have the same impact on the PDFs, and thus can be recognized as the same evidence for the inefficiency of perturbative QCD in dealing with charm production in some kinematic regions.

关键词： parton distribution functions heavy quark PDFs photon production Tevatron

Searching for a_(0)(980)-meson parton distribution function

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Communications in Theoretical Physics 2023年第8期75卷 111-118页

作者： Zai-Hui Wu Hai-Bing Fu Tao Zhong Yu Chen Ya-Hong Dai Department of Physics Guizhou Minzu UniversityGuiyang 550025China

In this paper,we calculate the scalar a_(0)(980)-meson leading-twist wave function by using the light-cone harmonic oscillator model(LCHO),where the model parameters are determined by fitting theξ-moments■of its light-cone distribution ***,the a_(0)(980)-meson leading-twist light-cone distribution amplitudes with three different scalesζ=(1.0,2.0,5.2)Ge V are *** constructing the relationship between the a_(0)(980)-meson leading-twist parton distribution functions/valence quark distribution function and its LCHO wave function,we exhibit the■(x,ζ)and■(x,ζ)with different ***,we also calculate the Mellin moments of the a_(0)(980)-meson’s valence quark distribution function■with n=(1,2,3),i.e.■=0.027,■=0.018 and■=***,the scale evolution for the ratio of the Mellin moments x■are presented.

关键词： parton distribution functions light-cone distribution amplitudes light scalar meson light-cone harmonic oscillator model

Regularization dependence of pion generalized parton distributions

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Chinese Physics C 2022年第6期46卷 66-87页

作者： Jin-Li Zhang Guang-Zhen Kang Jia-Lun Ping Department of Physics Nanjing Normal UniversityNanjing 210023China School of Science Yangzhou Polytechnic InstituteYangzhou 225127China

Pion generalized parton distributions are calculated within the framework of the Nambu-Jona-Lasinio model using different regularization schemes,including the proper time regularization scheme,the three-dimensional(3D)momentum cutoff scheme,the four-dimensional momentum cutoff scheme,and the Pauli-Villars regularization ***,we check the theoretical constraints of pion generalized parton distributions required by the symmetries of quantum chromodynamics in different regularization *** diagrams of pion parton distribution functions are plotted,in addition,we evaluate the Mellin moments of generalized parton distributions,which are related to the electromagnetic and gravitational form factors of *** generalized parton distributions are continuous but not differential at x=±ξ,when considering the effect of the contact contribution term,generalized parton distributions become not continuous at x=±ξin all the four regularization *** parton distributions in impact parameter space are considered,the width distribution of u quark in the pion and the meansquaredπu are *** light-front transverse-spin distributions are studied when quark polarized in the light-front-transverse+x direction,the transverse-spin density is no longer symmetric around(bx=0,by=0),the peaks shift to(bx=0,by>0),we compare the average transverse shift1u and2u in different regularization *** light-cone energy radius rE,LC and the light-cone charge radius rc,LC are also evaluated,we found that in the proper time regularization scheme the values of these quantities were the largest,in the 3 D momentum cutoff scheme they were the smallest.

关键词： generalized parton distributions form factors parton distribution functions

Collective Perspective on Advances in Dyson–Schwinger Equation QCD

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Communications in Theoretical Physics 2012年第7期58卷 79-134页

作者： Adnan Bashir Ian C.Clet Bruno El-Bennich Craig D.Roberts Peter C.Tandy Instituto de Física y Matemticas Universidad Michoacana de San Nicols de Hidalgo Edificio C-3Ciudad UniversitariaMoreliaMichoacn 58040Mxico Physics Division Argonne National Laboratory ArgonneIllinois 60439USA Center for Nuclear Research Department of PhysicsKent State UniversityKent OH 44242USA CSSM and CoEPP School of Chemistry and Physics University of AdelaideAdelaide SA 5005Australia Laboratorio de Física Teórica e Computao Científica Universidade Cruzeiro do Sul01506-000 So PauloSPBrazil Instituto de Física Torica Universidade Estadual Paulista01140-070 So PauloSPBrazil Department of Physics Center for High Energy Physics and State Key Laboratory of Nuclear Physics and TechnologyPeking University Institut für Kernphysik Forschungszentrum JülichD-52425 JülichGermany Department of Physics Illinois Institute of TechnologyChicagoIllinois 60616-3793USA

We survey contemporary studies of hadrons and strongly interacting quarks using QCD's Dyson-Schwinger equations, addressing the following aspects: confinement and dynamical chiral symmetry breaking; the hadron spectrum; hadron elastic and transition form factors, from small-to large-Q2; parton distribution functions; the physics of hadrons containing one or more heavy quarks; and properties of the quark gluon plasma.

关键词： confinement dynamical chiral symmetry breaking Dyson-Schwinger equations hadron spectrum hadron elastic and transition form factors heavy mesons in-hadron condensates parton distribution functions quark gluon plasma UA(1)-problem