scholarly journals Generalized Parton Distributions and the Structure of the Hadrons

2018 ◽  
Vol 47 ◽  
pp. 1860099
Author(s):  
O. V. Selyugin
Keyword(s):  
Form Factors ◽  
Distribution Functions ◽  
Electromagnetic Form Factors ◽  
Parton Distribution Functions ◽  
Parton Distributions ◽  
Hadron Interaction ◽  
High Energies ◽  
Generalized Parton Distributions ◽  
Momentum Transfer Dependence ◽  
The Impact

The dependence of the hadron interaction on its structure is examined in the framework of the generalized parton distributions (GPDs). The [Formula: see text] dependence of the GPDs is determined by the parton distribution functions (PDFs), which were obtained from the deep inelastic scattering. The analysis of the whole sets of experimental data on the electromagnetic form factors of the proton and neutron with taking into account many forms of PDFs, obtained by the different Collaborations, make it possible to obtain the special momentum transfer dependence of the GPDs. This permits us to obtain the electromagnetic and gravitomagnetic form factors of the nucleons. The impact parameter dependence of the proton and neutron charge and matter densities is examined. The elastic hadron scattering at high energies was analyzed in the framework of the model that takes into account both these form factors (electromagnetic and gravitomagnetic).

scholarly journals ON THE $\bar{d}/\bar{u}$ ASYMMETRY AND PARTON DISTRIBUTIONS

2002 ◽  
Vol 17 (02) ◽  
pp. 269-278
Author(s):  
ALEJANDRO DALEO ◽  
CARLOS A. GARCIA CANAL ◽  
GABRIELA A. NAVARRO ◽  
RODOLFO SASSOT
Keyword(s):  
Parton Distribution ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Parton Distributions ◽  
The Impact

We discuss the impact of different measurements of the [Formula: see text] asymmetry in the extraction of parametrizations of parton distribution functions.

scholarly journals GRAVITATION INTERACTION WITH EXTRA DIMENSION AND PERIODIC STRUCTURE OF THE HADRON SCATTERING AMPLITUDE

2011 ◽  
Vol 26 (28) ◽  
pp. 2109-2117
Author(s):  
O. V. SELYUGIN
Keyword(s):  
Periodic Structure ◽  
Interaction Potential ◽  
Extra Dimension ◽  
Scattering Amplitude ◽  
Form Factors ◽  
Parton Distributions ◽  
High Energies ◽  
Generalized Parton Distributions ◽  
Brane Models ◽  
Models Of Gravity

The behavior of the hadron scattering amplitude determined by the gravitation interaction of hadron at high energies with impact of the KK-modes in d-brane models of gravity is examined. The possible periodic structure of the scattering amplitude and its dependence from number of the additional dimensions are analyzed. The effects of the gravitational hadron form factors obtained from the hadron generalized parton distributions (GPDs) on the behavior of the interaction potential and the scattering amplitude are also analyzed. It is shown that in most part the periodic structure comes from the approximation of our calculations.

scholarly journals Recent highlights with baryons from lattice QCD

2020 ◽  
Vol 241 ◽  
pp. 02004
Author(s):  
Colin Morningstar
Keyword(s):  
Lattice Qcd ◽  
Percent Level ◽  
Form Factors ◽  
Distribution Functions ◽  
Electromagnetic Form Factors ◽  
Parton Distribution Functions ◽  
Quark Masses ◽  
Proton Mass ◽  
Key Points

Highlights from recent computations in lattice QCD involving baryons are presented. Calcula tions of the proton mass and spin decompositions are discussed, a percent level determination of the nucleon axial coupling is described, and determinations of the proton and neutron electromagnetic form factors and light-cone parton distribution functions are outlined. Recent results applying the so-called Luscher method to meson-baryon systems are presented. Key points emphasized are that much better precision with disconnected diagrams is being achieved, incorporating multi-hadron operators is now feasible, and more and more studies are being done with physical quark masses.

Investigating the impact of the partonic structure on the description of hadronic collisions at high energies

2020 ◽  
Vol 35 (22) ◽  
pp. 2050127
Author(s):  
M. Broilo ◽  
V. P. Gonçalves ◽  
P. V. R. G. Silva
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Proton Proton ◽  
High Energies ◽  
High Energy Behavior ◽  
Energy Behavior ◽  
The Impact ◽  
Hadronic Collisions

The impact of the partonic structure on the description of the hadronic cross-sections is investigated considering a multichannel eikonal model based on the Good–Walker approach. The total, elastic and single diffractive cross-sections are estimated considering different parametrizations for the parton distribution functions and the predictions are compared with the experimental data for proton–proton [Formula: see text] and antiproton–proton [Formula: see text] collisions. We show that the description of the high-energy behavior of the hadronic cross-sections is sensitive to the partonic structure.

scholarly journals Parton distributions in the LHC era

2018 ◽  
Vol 175 ◽  
pp. 01006 ◽  
Author(s):  
Luigi Del Debbio
Keyword(s):  
Experimental Data ◽  
First Principles ◽  
Short Distance ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Long Distance ◽  
Standard Description ◽  
Parton Distributions ◽  
Distance Properties ◽  
The Impact

Analyses of LHC (and other!) experiments require robust and statistically accurate determinations of the structure of the proton, encoded in the parton distribution functions (PDFs). The standard description of hadronic processes relies on factorization theorems, which allow a separation of process-dependent short-distance physics from the universal long-distance structure of the proton. Traditionally the PDFs are obtained from fits to experimental data. However, understanding the long-distance properties of hadrons is a nonperturbative problem, and lattice QCD can play a role in providing useful results from first principles. In this talk we compare the different approaches used to determine PDFs, and try to assess the impact of existing, and future, lattice calculations.

scholarly journals Recent progress on the study of nucleon structure from lattice QCD and future perspectives

2020 ◽  
Author(s):  
Constantia Alexandrou
Keyword(s):  
Lattice Qcd ◽  
Recent Progress ◽  
Form Factors ◽  
Distribution Functions ◽  
Nucleon Structure ◽  
Electromagnetic Form Factors ◽  
Momentum Fraction ◽  
Future Perspectives ◽  
Parton Distribution Functions ◽  
Quark Masses

We review the progress achieved within the last five years in the simulations of lattice QCD, as well as in the analysis for selected quantities probing nucleon structure. In particular, we discuss results on the nucleon electromagnetic form factors, \sigmaσ-terms, the momentum fraction carried by quark in the nucleon and the helicity and transversity moments. All quantities are obtained using simulations generated with quark masses fixed to their physical values. In addition, we review the on-going effort to extract parton distribution functions (PDFs) directly from lattice QCD using the quasi-PDF approach.

Transverse charge and magnetization densities based on Regge parameterization

2015 ◽  
Vol 24 (11) ◽  
pp. 1550086 ◽  
Author(s):  
Negin Sattary Nikkhoo ◽  
Mohammad Reza Shojaei
Keyword(s):  
Sum Rules ◽  
Form Factors ◽  
Transverse Plane ◽  
Large Momentum ◽  
Electromagnetic Form Factors ◽  
Parton Distributions ◽  
Generalized Parton Distributions ◽  
Transfer Region ◽  
Quark Charge ◽  
Elastic Form

In this paper, we discuss the charge and magnetization densities for proton and neutron in the transverse plane, whereas there are links between the generalized parton distributions (GPDs) and elastic form factors by means of sum rules. We use the extended Regge parameterization for large momentum transfer region for calculating Dirac and Pauli form factors which have been described in the electromagnetic form factors data, so we want to calculate the charge and magnetization densities for proton and neutron in the transverse plane and we also calculate [Formula: see text] and [Formula: see text] quark charge and magnetization densities. The extracted results are compared with other previous parameterizations.

scholarly journals Theory and applications of parton pseudodistributions

2020 ◽  
Vol 35 (05) ◽  
pp. 2030002 ◽  
Author(s):  
A. V. Radyushkin
Keyword(s):  
Time Distribution ◽  
Valence Quark ◽  
Basic Feature ◽  
Distribution Functions ◽  
Ultraviolet Divergence ◽  
Parton Distribution Functions ◽  
Parton Distributions ◽  
Gauge Link ◽  
Generalized Parton Distributions ◽  
Lorentz Invariants

We review the basic theory of the parton pseudodistributions approach and its applications to lattice extractions of parton distribution functions. The crucial idea of the approach is the realization that the correlator [Formula: see text] of the parton fields is a function [Formula: see text] of Lorentz invariants [Formula: see text], the Ioffe time, and the invariant interval [Formula: see text]. This observation allows to extract the Ioffe-time distribution [Formula: see text] from Euclidean separations [Formula: see text] accessible on the lattice. Another basic feature is the use of the ratio [Formula: see text], that allows to eliminate artificial ultraviolet divergence generated by the gauge link for spacelike intervals. The remaining [Formula: see text]-dependence of the reduced Ioffe-time distribution [Formula: see text] corresponds to perturbative evolution, and can be converted into the scale-dependence of parton distributions [Formula: see text] using matching relations. The [Formula: see text]-dependence of [Formula: see text] governs the [Formula: see text]-dependence of parton densities [Formula: see text]. The perturbative evolution was successfully observed in exploratory quenched lattice calculation. The analysis of its precise data provides a framework for extraction of parton densities using the pseudodistributions approach. It was used in the recently performed calculations of the nucleon and pion valence quark distributions. We also discuss matching conditions for the pion distribution amplitude and generalized parton distributions, the lattice studies of which are now in progress.

scholarly journals DIFFRACTIVE PHENOMENA

2002 ◽  
Vol 17 (23) ◽  
pp. 3204-3219
Author(s):  
GIUSEPPE IACOBUCCI
Keyword(s):  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Parton Distributions ◽  
Hadronic Interactions ◽  
Theoretical Approaches ◽  
Generalized Parton Distributions ◽  
Diffractive Scattering ◽  
Target Frame ◽  
Dipole Picture ◽  
Shed Light

The most recent theoretical and experimental results in the field of diffractive scattering are reviewed. A parallel between the two current theoretical approaches to diffraction, the DIS picture in the Breit frame and the dipole picture in the target frame, is given, accompanied by a description of the models to which the data are compared. A recent calculation of the rescattering corrections, which hints at the universality of the diffractive parton distribution functions, is presented. The concept of generalized parton distributions is discussed together with the first measurement of the processes which might give access to them. Particular emphasis is given to the HERA data, to motivate why hard diffraction in deep inelastic scattering is viewed as an unrivalled instrument to shed light on the still obscure aspects of hadronic interactions.

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.

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