Effects of next-to-leading order DGLAP evolution on generalized parton distributions of the proton and deeply virtual Compton scattering at high energy

Abstract

We studied the effects of NLO Q 2 evolution of generalized parton distributions (GPDs) using the alignedjet model for the singlet quark and gluon GPDs at an initial evolution scale. We found that the skewness ratio for quarks is a slow logarithmic function of Q 2 , reaching r S = 1.5−2 at Q 2 = 100 GeV 2 and r g ≈ 1 for gluons in a wide range of Q 2 . Using the resulting GPDs, we calculated the DVCS cross section on the proton in NLO pQCD and found that this model in conjunction with modern parameterizations of proton PDFs (CJ15 and CT14) provides a good description of the available H1 and ZEUS data in a wide kinematic range.

Nucleon axial form factor from generalized parton distributions

“…In this regard, the determination of polarized PDFs (PPDFs), which describe the structure of a nucleon in a helicity eigenstate, by performing a global analysis of available experimental data has also been of great interest [2][3][4][5][6][7][8][9][10][11][12][13]. On the other hand, the structure of nucleon both in unpolarized and polarized cases can be investigated in more detail using generalized parton distributions (GPDs) [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] which comprise important concepts of Quantum Chromodynamics (QCD). Actually, GPDs provide quantitative information on the longitudinal and transverse distribution of partons inside the nucleon, and also their intrinsic and orbital angular momenta.…”

“…Although early studies of GPDs using various dynamical models of the nucleon structure (see Ref. [28] and references therein) have played an important role for better understanding of GPDs and exclusive processes, but at the moment, more attention is being paid to determine GPDs from fitting the available experimental data (see Ref. [27] and references therein).…”

Determination of generalized parton distributions through a simultaneous analysis of axial form factor and wide-angle Compton scattering data

“…Although the first Mellin moments of GPDs in special cases can be determined from the lattice QCD calculations [33,34] and also there are early studies of GPDs using various dynamical models of the nucleon structure [38], the well-established method to extract GPDs is analyzing the related experimental data through a QCD fit [37], same as for the PDFs and PPDFs. To this end, there have been various models [79][80][81][82][83][84] and parameterizations [85][86][87] for GPDs during the last two decades.…”

QCD analysis of non-singlet structure functions at NNLO accuracy, based on the Laplace transform

“…As usual, by fitting the available experimental data including the DIS processes and the ones from hadron colliders [1][2][3][4][5][6][7][8][9][10], these nonperturbative PDFs can be determined. To get numerical solutions for the evolved nonsinglet PDFs, there are different methods such as the Brute-force [11][12][13], the Laguerre transformation technique [14][15][16][17][18][19] and the Mellin-transform [20][21][22][23][24], and for analytical solutions we can refer to the Jacobi polynomi-als model [25,26] as well as the Laplace transformation technique [27][28][29].…”