scholarly journals The continuum and leading twist limits of parton distribution functions in lattice QCD

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Joseph Karpie ◽  
Kostas Orginos ◽  
Anatoly Radyushkin ◽  
Savvas Zafeiropoulos ◽  
Keyword(s):  
Lattice Qcd ◽  
Parton Distribution ◽  
Continuum Limit ◽  
Jacobi Polynomials ◽  
Parton Distribution Function ◽  
Systematic Errors ◽  
Distribution Functions ◽  
Matrix Elements ◽  
Parton Distribution Functions ◽  
The Continuum

Abstract In this study, we present continuum limit results for the unpolarized parton distribution function of the nucleon computed in lattice QCD. This study is the first continuum limit using the pseudo-PDF approach with Short Distance Factorization for factorizing lattice QCD calculable matrix elements. Our findings are also compared with the pertinent phenomenological determinations. Inter alia, we are employing the summation Generalized Eigenvalue Problem (sGEVP) technique in order to optimize our control over the excited state contamination which can be one of the most serious systematic errors in this type of calculations. A crucial novel ingredient of our analysis is the parameterization of systematic errors using Jacobi polynomials to characterize and remove both lattice spacing and higher twist contaminations, as well as the leading twist distribution. This method can be expanded in further studies to remove all other systematic errors.

scholarly journals QCD Factorization and PDFs from Lattice QCD Calculation

2015 ◽  
Vol 37 ◽  
pp. 1560041 ◽  
Author(s):  
Yan-Qing Ma ◽  
Jian-Wei Qiu
Keyword(s):  
Euclidean Space ◽  
Minkowski Space ◽  
Lattice Qcd ◽  
Correlation Functions ◽  
Parton Distribution ◽  
Distribution Functions ◽  
Matrix Elements ◽  
Parton Distribution Functions ◽  
Qcd Factorization ◽  
The Matrix

In this talk, we review a QCD factorization based approach to extract parton distribution and correlation functions from lattice QCD calculation of single hadron matrix elements of quark-gluon operators. We argue that although the lattice QCD calculations are done in the Euclidean space, the nonperturbative collinear behavior of the matrix elements are the same as that in the Minkowski space, and could be systematically factorized into parton distribution functions with infrared safe matching coefficients. The matching coefficients can be calculated perturbatively by applying the factorization formalism on to asymptotic partonic states.

RECENT PROGRESS ON NUCLEON STRUCTURE WITH LATTICE QCD

2014 ◽  
Vol 25 ◽  
pp. 1460039 ◽  
Author(s):  
HUEY-WEN LIN
Keyword(s):  
Lattice Qcd ◽  
Parton Distribution ◽  
Recent Progress ◽  
Distribution Functions ◽  
Nucleon Structure ◽  
Matrix Elements ◽  
Parton Distribution Functions ◽  
Bjorken X ◽  
Systematic Control ◽  
Made In

I review recent progress made in the calculation of nucleon structure in lattice QCD. Due to space limitations, I will focus on a few specific topics: systematic control of lattice-QCD matrix elements, probing TeV-physics with the aid of nucleon tensor and scalar charges, and Bjorken-x dependence of nucleon parton distribution functions.

scholarly journals Parton distribution functions on the lattice and in the continuum

2018 ◽  
Vol 175 ◽  
pp. 06032 ◽  
Author(s):  
Joseph Karpie ◽  
Kostas Orginos ◽  
Anatoly Radyushkin ◽  
Savvas Zafeiropoulos
Keyword(s):  
Numerical Calculation ◽  
First Principles ◽  
Parton Distribution ◽  
Fourier Transforms ◽  
Distribution Functions ◽  
Matrix Elements ◽  
Momentum Fraction ◽  
Parton Distribution Functions ◽  
Equal Time ◽  
The Continuum

Ioffe-time distributions, which are functions of the Ioffe-time ν, are the Fourier transforms of parton distribution functions with respect to the momentum fraction variable x. These distributions can be obtained from suitable equal time, quark bilinear hadronic matrix elements which can be calculated from first principles in lattice QCD, as it has been recently argued. In this talk I present the first numerical calculation of the Ioffe-time distributions of the nucleon in the quenched approximation.

scholarly journals Unraveling high-energy hadron structures with lattice QCD

2018 ◽  
Vol 33 (36) ◽  
pp. 1830033 ◽  
Author(s):  
Yong Zhao
Keyword(s):  
Distribution Function ◽  
Lattice Qcd ◽  
Parton Distribution ◽  
Parton Distribution Function ◽  
High Energy ◽  
Distribution Functions ◽  
Effective Theory ◽  
Large Momentum ◽  
Parton Distribution Functions ◽  
Factorization Formula

Parton distribution functions are key quantities for us to understand the hadronic structures in high-energy scattering, but they are difficult to calculate from lattice QCD. Recent years have seen fast development of the large-momentum effective theory which allows extraction of the x-dependence of parton distribution functions from a quasi-parton distribution function that can be directly calculated on lattice. The extraction is based on a factorization formula for the quasi-parton distribution function that has been derived rigorously in perturbation theory. A systematic procedure that includes renormalization, perturbative matching, and power corrections has been established to calculate parton distribution functions. Latest progress from lattice QCD has shown promising signs that it will become an effective tool for calculating parton physics.

scholarly journals Light-Cone Parton Distribution Functions from Lattice QCD

2018 ◽  
Vol 121 (11) ◽  
Author(s):  
Constantia Alexandrou ◽  
Krzysztof Cichy ◽  
Martha Constantinou ◽  
Karl Jansen ◽  
Aurora Scapellato ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Parton Distribution ◽  
Light Cone ◽  
Distribution Functions ◽  
Parton Distribution Functions

scholarly journals Parton Distribution Functions and Lattice QCD

2019 ◽  
Vol 206 ◽  
pp. 01003
Author(s):  
Huey-Wen Lin
Keyword(s):  
Lattice Qcd ◽  
Parton Distribution ◽  
Pion Mass ◽  
Effective Field ◽  
Distribution Functions ◽  
Large Momentum ◽  
Parton Distribution Functions ◽  
Proton Structure ◽  
Nonperturbative Renormalization ◽  
First Time

Recently, there have been rapid developments in lattice-QCD calculations of proton structure, especially in the parton distribution functions (PDFs). We overcame a longstanding obstacle and for the first time in lattice-QCD are able to directly calculate the Bjorken-x dependence of the quark, helicity and transversity distributions. The PDFs are obtained using the large-momentum effective field theory (LaMET) framework where the full Bjorken-x dependence of finite-momentum PDFs, called “quasi-PDFs”, can be calculated on the lattice. The quasi-PDF nucleon matrix elements are renormalized non-perturbatively in RI/MOM-scheme. Following a nonperturbative renormalization of the parton quasi-distribution in a regularization-independent momentum-subtraction scheme, we establish its matching to the $ \overline {{\rm{MS}}} $ PDF and calculate the non-singlet matching coefficient at next-to-leading order in perturbation theory. In this proceeding, I will show the progress that has been made in recent years, highlighting the latest state-of-the art PDF calculations at the physical pion mass. Future impacts on the large-x global PDF fits are also discussed.

scholarly journals Progress in computing parton distribution functions from the quasi-PDF approach

2018 ◽  
Vol 175 ◽  
pp. 06021 ◽  
Author(s):  
Constantia Alexandrou ◽  
Krzysztof Cichy ◽  
Martha Constantinou ◽  
Kyriakos Hadjiyiannakou ◽  
Karl Jansen ◽  
...  
Keyword(s):  
Parton Distribution ◽  
Distribution Functions ◽  
Matrix Elements ◽  
Parton Distribution Functions ◽  
Mass Collaboration ◽  
Twisted Mass ◽  
The Future ◽  
Systematic Effects ◽  
Perturbative Renormalization

We discuss the current developments by the European Twisted Mass Collaboration in extracting parton distribution functions from the quasi-PDF approach. We concentrate on the non-perturbative renormalization prescription recently developed by us, using the RI′ scheme. We show results for the renormalization functions of matrix elements needed for the computation of quasi-PDFs, including the conversion to the MS scheme, and for renormalized matrix elements. We discuss the systematic effects present in the Z-factors and the possible ways of addressing them in the future.

scholarly journals Pion parton distribution functions from lattice QCD

2004 ◽  
Vol 129-130 ◽  
pp. 281-283 ◽  
Author(s):  
I. Wetzorke ◽  
M. Guagnelli ◽  
K. Jansen ◽  
F. Palombi ◽  
R. Petronzio ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Parton Distribution ◽  
Distribution Functions ◽  
Parton Distribution Functions
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