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Generalized parton distribution (GPD) contains rich information of partons in a hadron, including transverse profile, and is also non-perturbative information necessary in describing a variety of hard processes, such as meson…

High Energy Physics - Phenomenology · Physics 2015-05-28 Ryoichi Nishio , Taizan Watari

Recently the calculations of all five-parton one-loop QCD amplitudes have been completed. In this letter we describe how to get the corresponding amplitudes with one gluon replaced by a photon and we give the explicit results for the…

High Energy Physics - Phenomenology · Physics 2009-10-28 Adrian Signer

The DGLAP, BFKL, modified DGLAP and modified BFKL equations are constructed in a unified partonic framework. The antishadowing effect in the recombination process is emphasized, which leads to two different small $x$ behaviors of gluon…

High Energy Physics - Phenomenology · Physics 2007-05-23 Wei Zhu , Zhenqi Shen , Jifeng Yang , Jianhong Ruan

We solve a unified integral equation to obtain the $x, Q_T$ and $Q$ dependence of the gluon distribution of a proton in the small $x$ regime; where $x$ and $Q_T$ are the longitudinal momentum fraction and the transverse momentum of the…

High Energy Physics - Phenomenology · Physics 2014-11-17 J. Kwiecinski , A. D. Martin , P. J. Sutton

The parton distributions in the proton are evaluated dynamically using a nonlinear QCD evolution equation - the DGLAP equation with twist-4 (the GLR-MQ-ZSR) corrections - starting from a low scale $\mu^2$, where the nucleon consists of…

High Energy Physics - Phenomenology · Physics 2014-09-11 Xurong Chen , Jianhong Ruan , Rong Wang , Pengming Zhang , Wei Zhu

Parton branching solutions of QCD evolution equations have recently been studied to construct both collinear and transverse momentum dependent (TMD) parton distributions. In this formalism, a soft-gluon resolution scale is introduced to…

High Energy Physics - Phenomenology · Physics 2022-07-28 S. Sadeghi Barzani

We compute the twist-2 matching of the transverse-momentum-dependent (TMD) linearly polarized gluon parton distribution and fragmentation functions at next-to-next-to-next-to-leading order (N$^3$LO) in QCD, supplemented by…

High Energy Physics - Phenomenology · Physics 2026-04-07 Yu Jiao Zhu

We consider for the first time the QED corrections to the evolution of (un)polarized quark and gluon transverse-momentum-dependent distribution and fragmentation functions (TMDs in general). By extending their operator definition to…

High Energy Physics - Phenomenology · Physics 2018-11-21 Alessandro Bacchetta , Miguel G. Echevarria

We study the global analysis for parton distributions as a function of the QCD strong coupling strength alpha_s, and present a new series of distributions that span the range 0.110 < alpha_s(m_Z) < 0.128. We use these distributions to…

High Energy Physics - Phenomenology · Physics 2009-11-11 J. Pumplin , A. Belyaev , J. Huston , D. Stump , W. K. Tung

We study the global Q^2 dependence of large x, F_2 nucleon structure function data, with the aim of providing a perturbative-QCD based, quantitative analysis of parton-hadron duality. As opposed to previous analyses at fixed x, we use a…

High Energy Physics - Phenomenology · Physics 2014-11-17 S. Liuti , R. Ent , C. E. Keppel , I. Niculescu

In this paper I show that it is possible to use Regge theory to constrain the initial parton distribution functions of a global DGLAP fit. In this approach, both quarks and gluons have the same high-energy behaviour which may also be used…

High Energy Physics - Phenomenology · Physics 2014-11-17 Gregory Soyez

In QCD the gauge-invariant gluon polarization Delta G in a nucleon can be defined either in a non-local way as the integral over the Ioffe-time distribution of polarized gluons, or in light-cone gauge as the forward matrix element of the…

High Energy Physics - Phenomenology · Physics 2011-09-13 A. Saalfeld , G. Piller , L. Mankiewicz

Sum rules for twist-3 distributions are reexamined. Integral relations between twist-3 and twist-2 parton distributions suggest the possibility for a $\delta$-function at $x=0$. We confirm and clarify this result by constructing $h_L$ and…

High Energy Physics - Phenomenology · Physics 2009-11-07 M. Burkardt , Y. Koike

We define in the framework of light-cone collinear factorization method, the chiral-odd generalized parton distributions (GPDs) of a pseudoscalar hadron (such as the $\pi^0$) up to twist 6. For that, we introduce the relevant matrix…

High Energy Physics - Phenomenology · Physics 2014-07-25 B. Pire , L. Szymanowski , S. Wallon

Applications of perturbative QCD to deeply virtual Compton scattering and hard exclusive electroproduction processes require a generalization of the usual parton distributions for the case when long-distance information is accumulated in…

High Energy Physics - Phenomenology · Physics 2016-11-23 A. V. Radyushkin

We demonstrate the QCD factorization for inclusive hadron production in $pA$ collisions in the saturation formalism at one-loop order, with explicit calculation of both real and virtual gluon radiation diagrams. The collinear divergences…

High Energy Physics - Phenomenology · Physics 2013-05-30 Giovanni A. Chirilli , Bo-Wen Xiao , Feng Yuan

We present the first open-source analysis of parton distribution functions (PDFs) of charged pions using xFitter, an open-source QCD fit framework to facilitate PDF extraction and analyses. Our calculations are implemented at…

We study the unpolarized gluon quasidistribution function in the nucleon at one loop level in the large momentum effective theory. For the quark quasidistribution, power law ultraviolet divergences arise in the cut-off scheme and an…

High Energy Physics - Phenomenology · Physics 2018-02-22 Wei Wang , Shuai Zhao , Ruilin Zhu

We present preliminary results on the leading-twist transverse-momentum-dependent (TMD) gluon linearity function, which is directly connected to nucleon transverse-spin asymmetries originating from the density of linearly-polarized gluons.…

High Energy Physics - Phenomenology · Physics 2022-03-11 Alessandro Bacchetta , Francesco Giovanni Celiberto , Marco Radici

We 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…

High Energy Physics - Phenomenology · Physics 2021-06-03 Chengdong Han , Gang Xie , Rong Wang , Xurong Chen