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Title: Exploring Partonic Structure of Hadrons Using ab initio Lattice QCD Calculations

Abstract

Following our previous proposal, we construct a class of good "lattice cross sections" (LCSs), from which we can study the partonic structure of hadrons from ab initio lattice QCD calculations. These good LCSs, on the one hand, can be calculated directly in lattice QCD, and on the other hand, can be factorized into parton distribution functions (PDFs) with calculable coefficients, in the same way as QCD factorization for factorizable hadronic cross sections. PDFs could be extracted from QCD global analysis of the lattice QCD generated data of LCSs. In conclusion, we also show that the proposed functions for lattice QCD calculation of PDFs in the literature are special cases of these good LCSs.

Authors:
 [1];  [2]
  1. Peking Univ., Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)
  2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States). Theory Center
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
OSTI Identifier:
1416474
Report Number(s):
JLAB-THY-17-2542; DOE/OR/-23177-4216; arXiv:1709.03018
Journal ID: ISSN 0031-9007; PRLTAO
Grant/Contract Number:
AC05-06OR23177
Resource Type:
Journal Article: Published Article
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 120; Journal Issue: 2; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Ma, Yan-Qing, and Qiu, Jian-Wei. Exploring Partonic Structure of Hadrons Using ab initio Lattice QCD Calculations. United States: N. p., 2018. Web. doi:10.1103/PhysRevLett.120.022003.
Ma, Yan-Qing, & Qiu, Jian-Wei. Exploring Partonic Structure of Hadrons Using ab initio Lattice QCD Calculations. United States. doi:10.1103/PhysRevLett.120.022003.
Ma, Yan-Qing, and Qiu, Jian-Wei. 2018. "Exploring Partonic Structure of Hadrons Using ab initio Lattice QCD Calculations". United States. doi:10.1103/PhysRevLett.120.022003.
@article{osti_1416474,
title = {Exploring Partonic Structure of Hadrons Using ab initio Lattice QCD Calculations},
author = {Ma, Yan-Qing and Qiu, Jian-Wei},
abstractNote = {Following our previous proposal, we construct a class of good "lattice cross sections" (LCSs), from which we can study the partonic structure of hadrons from ab initio lattice QCD calculations. These good LCSs, on the one hand, can be calculated directly in lattice QCD, and on the other hand, can be factorized into parton distribution functions (PDFs) with calculable coefficients, in the same way as QCD factorization for factorizable hadronic cross sections. PDFs could be extracted from QCD global analysis of the lattice QCD generated data of LCSs. In conclusion, we also show that the proposed functions for lattice QCD calculation of PDFs in the literature are special cases of these good LCSs.},
doi = {10.1103/PhysRevLett.120.022003},
journal = {Physical Review Letters},
number = 2,
volume = 120,
place = {United States},
year = 2018,
month = 1
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevLett.120.022003

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  • Following our previous proposal, we construct a class of good "lattice cross sections" (LCSs), from which we can study the partonic structure of hadrons from ab initio lattice QCD calculations. These good LCSs, on the one hand, can be calculated directly in lattice QCD, and on the other hand, can be factorized into parton distribution functions (PDFs) with calculable coefficients, in the same way as QCD factorization for factorizable hadronic cross sections. PDFs could be extracted from QCD global analysis of the lattice QCD generated data of LCSs. In conclusion, we also show that the proposed functions for lattice QCDmore » calculation of PDFs in the literature are special cases of these good LCSs.« less
  • The Drell-Yan process is a standard tool for probing the partonic structure of hadrons. Since the process proceeds through a quark-antiquark annihilation, Drell-Yan scattering possesses a unique ability to selectively probe sea distributions. This review examines the application of Drell-Yan scattering to elucidating the flavor asymmetry of the nucleon's sea and nuclear modifications to the sea quark distributions in unpolarized scattering. Polarized beams and targets add an exciting new dimension to Drell-Yan scattering. In particular, the two initial-state hadrons give Drell-Yan sensitivity to chirally odd transversity distributions.
  • Calculations of processes that depend on electronic states or charge transfer in bulk glasses are challenging because of the limitations imposed by the need to use ab initio methods. Cluster-based calculations alone cannot capture the response of the network structure that occurs upon bond rupturing or other alteration of the local molecular framework. From the atomic level perspective, it is necessary that simulations of extended (bulk) amorphous systems sample a large number of possible geometrical arrangements of molecular structures as well as their frequency and relative spatial distribution. To acheive this in sample sizes amenable to ab initio methods, wemore » create multiple controlled samples, that as an ensemble provide a good statistical sampling of the bulk structure. In this work, glass samples are first generated using classical molecular dynamics then transferred to ab initio molecular dynamics where the samples are optimized using density functional theory. The optimal structures obtained by classical molecular dynamics (MD) and ab initio MD methods are compared to each other and to the classical simulation of a larger system.« less
  • The accuracy of a single s-orbital representation of Cu towards enabling multi-thousand atom ab initio calculations of electronic structure is evaluated in this work. If an electrostatic compensation charge of 0.3 electron per atom is used in this basis representation, the electronic transmission in bulk and nanocrystalline Cu can be made to compare accurately to that obtained with a Double Zeta Polarized basis set. The use of this representation is analogous to the use of single band effective mass representation for semiconductor electronic structure. With a basis of just one s-orbital per Cu atom, the representation is extremely computationally efficientmore » and can be used to provide much needed ab initio insight into electronic transport in nanocrystalline Cu interconnects at realistic dimensions of several thousand atoms.« less
  • Experimental and ab initio computational methods are employed to conclusively show that ScN is a semiconductor rather than a semimetal; i.e., there is a gap between the N 2p and the Sc 3d bands. Previous experimental investigators reported, in agreement with band structure calculations showing a band overlap of 0.2 eV, that ScN is a semimetal while others concluded that it is a semiconductor with a band gap larger than 2 eV. We have grown high quality, single crystalline ScN layers on MgO(001) and on TiN(001) buffer layers on MgO(001) by ultrahigh vacuum reactive magnetron sputter deposition. ScN optical propertiesmore » were determined by transmission, reflection, and spectroscopic ellipsometry while in-situ x-ray and ultraviolet valence band photoelectron spectroscopy were used to determine the density of states (DOS) below the Fermi level. The measured DOS exhibits peaks at 3.8 and 5.2 eV stemming from the N 2p bands and at 15.3 eV due to the N 2s bands. The imaginary part of the measured dielectric function {epsilon}{sub 2} consists of two primary features due to direct X- and {Gamma}-point transitions at photon energies of 2.7 and 3.8 eV, respectively. For comparison, the ScN band structure was calculated using an ab initio Kohn--Sham approach which treats the exchange interactions exactly within density-functional theory. Calculated DOS and the complex dielectric function are in good agreement with our ScN valence-band photoelectron spectra and measured optical properties, respectively. We conclude, combining experimental and computational results, that ScN is a semiconductor with an indirect {Gamma}--X bandgap of 1.3{+-}0.3eV and a direct X-point gap of 2.4{+-}0.3eV.« less