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We present the resolution of a long-standing discrepancy between the moments of parton distributions calculated from lattice QCD and their experimental values. We propose a simple extrapolation formula for the moments of the nonsinglet…

High Energy Physics - Lattice · Physics 2008-11-26 W. Detmold , W. Melnitchouk , J. W. Negele , D. B. Renner , A. W. Thomas

A better understanding of transverse momentum (k_T-) dependent quark distributions in a hadron is needed to interpret several experimentally observed large angular asymmetries and to clarify the fundamental role of gauge links in…

High Energy Physics - Lattice · Physics 2010-01-15 Ph. Hägler , B. U. Musch , J. W. Negele , A. Schäfer

The strong force which binds hadrons is described by the theory of quantum chromodynamics (QCD). Determining the character and manifestations of QCD is one of the most important and challenging outstanding issues necessary for a…

High Energy Physics - Lattice · Physics 2025-06-06 Huey-Wen Lin

We present recent results on the first moments of parton distributions using gauge configurations generated with two degenerate flavors of light twisted mass quarks with pion mass fixed approximately to its physical value. We also present a…

High Energy Physics - Lattice · Physics 2016-04-20 Constantia Alexandrou

In the large momentum transfer limit, generalized parton distributions can be calculated through a QCD factorization theorem which involves perturbatively-calculable hard kernels and light-cone parton distribution amplitudes of hadrons. We…

High Energy Physics - Phenomenology · Physics 2009-11-10 Pervez Hoodbhoy , Xiangdong Ji , Feng Yuan

I begin by discussing the basic ideas of quantum field theory (QFT). I provide a review of symmetries in physics and then move on to discuss the quark model. I then review lattice gauge theory with particular attention paid to lattice QCD…

High Energy Physics - Lattice · Physics 2009-09-29 W Armour

I discuss how generalized parton distribution probe various aspects of QCD bound states. Topics include the interplay between transverse and longitudinal structure, quantum mechanical interference, orbital angular momentum, helicity flip,…

High Energy Physics - Phenomenology · Physics 2009-11-07 M. Diehl

Three-body decay functions in space-like parton branches are implemented to evaluate transverse-momentum-dependent (TMD) parton distribution functions in the next-to-leading logarithmic (NLL) order of quantum chromodynamics (QCD).…

High Energy Physics - Phenomenology · Physics 2015-04-08 Hidekazu Tanaka

By determining the quark momentum fractions of the octet baryons from N_f=2+1 lattice simulations, we are able to predict the degree of charge symmetry violation in the parton distribution functions of the nucleon. This is of importance,…

High Energy Physics - Lattice · Physics 2011-05-10 R. Horsley , Y. Nakamura , D. Pleiter , P. E. L. Rakow , G. Schierholz , H. Stüben , A. W. Thomas , F. Winter , R. D. Young , J. M. Zanotti

Parton distribution functions (DFs) have long been recognised as key measures of hadron structure. Today, theoretical prediction of such DFs is becoming possible using diverse methods for continuum and lattice analyses of strong interaction…

High Energy Physics - Phenomenology · Physics 2024-11-12 Yang Yu , Craig D. Roberts

Parton distribution functions and hadronic tensors may be computed on a universal quantum computer without many of the complexities that apply to Euclidean lattice calculations. We detail algorithms for computing parton distribution…

High Energy Physics - Lattice · Physics 2020-03-18 Henry Lamm , Scott Lawrence , Yukari Yamauchi

After a brief recapitulation of the general interest of parton densities, we discuss multiple hard interactions and multiparton distributions. We report on recent theoretical progress in their QCD description, on outstanding conceptual…

High Energy Physics - Phenomenology · Physics 2015-06-03 Markus Diehl

State-of-the-art lattice QCD simulations enable the evaluation of nucleon form factors and Mellin moments with controlled systematics, yielding results with unprecedented accuracy. At the same time, new theoretical approaches are allowing…

High Energy Physics - Lattice · Physics 2024-01-30 Constantia Alexandrou , Simone Bacchio

Within a chiral quark model, we evaluate the good cross section in the Euclidean space in the vector - axial vector channel, proposed recently by Ma and Qiu as means to extract the so far elusive parton distribution functions of the pion…

High Energy Physics - Phenomenology · Physics 2020-09-28 Wojciech Broniowski , Enrique Ruiz Arriola

The partons' transverse momentum can be explored with QCD lattice simulations by studying the quasi-transverse-momentum-dependent parton distribution functions (qTMDPDFs), which are factorized in terms of physical TMDPDFs and soft factors…

High Energy Physics - Phenomenology · Physics 2023-12-19 Óscar del Río , Alexey Vladimirov

We report on our exploratory study for the evaluation of the parton distribution functions from lattice QCD, based on a new method proposed in Ref.~arXiv:1305.1539. Using the example of the nucleon, we compare two different methods to…

We present results on the spin carried by quarks and gluons in the nucleon using lattice QCD simulations with physical values of the light, strange and charm quark masses. We also discuss selective results on the x-dependence of parton…

High Energy Physics - Lattice · Physics 2023-01-18 Constantia Alexandrou

Ioffe-time distributions, which are functions of the Ioffe-time $\nu$, are the Fourier transforms of parton distribution functions with respect to the momentum fraction variable $x$. These distributions can be obtained from suitable equal…

High Energy Physics - Lattice · Physics 2018-04-18 Joseph Karpie , Kostas Orginos , Anatoly Radyushkin , Savvas Zafeiropoulos

The calculation of generalized parton distributions (GPDs) in lattice QCD was traditionally done by calculating matrix elements in the symmetric frame. Recent advancements have significantly reduced computational costs by calculating these…

We investigate the connection of lattice calculations of moments of isovector parton distributions to the physical regime through extrapolations in the quark mass. We consider the one pion loop renormalisation of the nucleon matrix elements…

High Energy Physics - Lattice · Physics 2009-11-07 W. Detmold , W. Melnitchouk , A. W. Thomas