scholarly journals Double parton distributions in the nucleon from lattice QCD

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Gunnar S. Bali ◽  
Markus Diehl ◽  
Benjamin Gläßle ◽  
Andreas Schäfer ◽  
Christian Zimmermann
Keyword(s):  
Lattice Qcd ◽  
Parton Distributions ◽  
Mellin Moment ◽  
Quark Flavor ◽  
Almost All

Abstract We evaluate nucleon four-point functions in the framework of lattice QCD in order to extract the first Mellin moment of double parton distributions (DPDs) in the unpolarized proton. In this first study, we employ an nf = 2+1 ensemble with pseudoscalar masses of mπ = 355 MeV and mK = 441 MeV. The results are converted to the scale μ = 2 GeV. Our calculation includes all Wick contractions, and for almost all of them a good statistical signal is obtained. We analyze the dependence of the DPD Mellin moments on the quark flavor and the quark polarization. Furthermore, the validity of frequently used factorization assumptions is investigated.

scholarly journals Double parton distributions in the pion from lattice QCD

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Gunnar S. Bali ◽  
Luca Castagnini ◽  
Markus Diehl ◽  
Jonathan R. Gaunt ◽  
Benjamin Gläßle ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Lattice Qcd ◽  
Quark Mass ◽  
Matrix Elements ◽  
Parton Distributions ◽  
Almost All ◽  
The Relationship

Abstract We perform a lattice study of double parton distributions in the pion, using the relationship between their Mellin moments and pion matrix elements of two local currents. A good statistical signal is obtained for almost all relevant Wick contractions. We investigate correlations in the spatial distribution of two partons in the pion, as well as correlations involving the parton polarisation. The patterns we observe depend significantly on the quark mass. We investigate the assumption that double parton distributions approximately factorise into a convolution of single parton distributions.

scholarly journals Moments of nucleon generalized parton distributions in lattice QCD

2003 ◽  
Vol 68 (3) ◽  
Author(s):  
Ph. Hägler ◽  
J. W. Negele ◽  
D. B. Renner ◽  
W. Schroers ◽  
Th. Lippert ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Parton Distributions ◽  
Generalized Parton Distributions

scholarly journals Parton Distributions from Lattice QCD with momentum smearing

2017 ◽  
Author(s):  
Christian Wiese ◽  
Constantia Alexandrou ◽  
Krzysztof Cichy ◽  
Martha Constantinou ◽  
Kyriakos Hadjiyiannakou ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Parton Distributions

scholarly journals Transverse Structure of Nucleon Parton Distributions from Lattice QCD

2004 ◽  
Vol 93 (11) ◽  
Author(s):  
Ph. Hägler ◽  
J. W. Negele ◽  
D. B. Renner ◽  
W. Schroers ◽  
Th. Lippert ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Parton Distributions ◽  
Transverse Structure

scholarly journals A Guide to Light-Cone PDFs from Lattice QCD: An Overview of Approaches, Techniques, and Results

2019 ◽  
Vol 2019 ◽  
pp. 1-68 ◽  
Author(s):  
Krzysztof Cichy ◽  
Martha Constantinou
Keyword(s):  
Lattice Qcd ◽  
Cross Sections ◽  
Light Cone ◽  
Distribution Functions ◽  
Strong Interactions ◽  
Parton Distribution Functions ◽  
Hadronic Tensor ◽  
Parton Distributions ◽  
Transverse Momentum Dependent ◽  
The Rich

Within the theory of Quantum Chromodynamics (QCD), the rich structure of hadrons can be quantitatively characterized, among others, using a basis of universal nonperturbative functions: parton distribution functions (PDFs), generalized parton distributions (GPDs), transverse momentum dependent parton distributions (TMDs), and distribution amplitudes (DAs). For more than half a century, there has been a joint experimental and theoretical effort to obtain these partonic functions. However, the complexity of the strong interactions has placed severe limitations, and first-principle information on these distributions was extracted mostly from their moments computed in Lattice QCD. Recently, breakthrough ideas changed the landscape and several approaches were proposed to access the distributions themselves on the lattice. In this paper, we review in considerable detail approaches directly related to partonic distributions. We highlight a recent idea proposed by X. Ji on extracting quasidistributions that spawned renewed interest in the whole field and sparked the largest amount of numerical studies within Lattice QCD. We discuss theoretical and practical developments, including challenges that had to be overcome, with some yet to be handled. We also review numerical results, including a discussion based on evolving understanding of the underlying concepts and the theoretical and practical progress. Particular attention is given to important aspects that validated the quasidistribution approach, such as renormalization, matching to light-cone distributions, and lattice techniques. In addition to a thorough discussion of quasidistributions, we consider other approaches: hadronic tensor, auxiliary quark methods, pseudodistributions, OPE without OPE, and good lattice cross-sections. In the last part of the paper, we provide a summary and prospects of the field, with emphasis on the necessary conditions to obtain results with controlled uncertainties.

scholarly journals Progress in resolving charge symmetry violation in nucleon structure

2014 ◽  
Vol 23 (07) ◽  
pp. 1461010
Author(s):  
R. D. Young ◽  
P. E. Shanahan ◽  
A. W. Thomas
Keyword(s):  
Lattice Qcd ◽  
Recent Work ◽  
Mass Difference ◽  
Baryon Octet ◽  
Nucleon Structure ◽  
Symmetry Violation ◽  
Charge Symmetry ◽  
Parton Distributions

Recent work unambiguously resolves the level of charge symmetry violation in moments of parton distributions using (2 + 1)-flavor lattice QCD. We introduce the methods used for that analysis by applying them to determine the strong contribution to the proton–neutron mass difference. We also summarize related work which reveals that the fraction of baryon spin which is carried by the quarks is in fact structure-dependent rather than universal across the baryon octet.

scholarly journals Helicity dependent and independent generalized parton distributions of the nucleon in lattice QCD

2005 ◽  
Vol 24 (S1) ◽  
pp. 29-33 ◽  
Author(s):  
P. Hägler ◽  
J.W. Negele ◽  
D.B. Renner ◽  
W. Schroers ◽  
T. Lippert ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Parton Distributions ◽  
Generalized Parton Distributions

scholarly journals Aspects of Lattice QCD Calculations of Transverse Momentum-Dependent Parton Distributions

2016 ◽  
Author(s):  
Michael Engelhardt ◽  
Bernhard Musch ◽  
Tanmoy Bhattacharya ◽  
Jeremy R. Green ◽  
Rajan Gupta ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Lattice Qcd ◽  
Parton Distributions ◽  
Transverse Momentum Dependent
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