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Proton matrix elements of the QCD energy-momentum tensor (EMT) are expressed by the gravitational form factors. The forward values of the gravitational form factors allow for a decomposition of the proton mass into contributions from quarks…

High Energy Physics - Phenomenology · Physics 2026-03-18 Kazuhiro Tanaka

Lattice simulations of QCD have produced precise estimates for the masses of the lowest-lying hadrons which show excellent agreement with experiment. By contrast, lattice results for the vector and axial vector form factors of the nucleon…

High Energy Physics - Lattice · Physics 2011-09-23 B. B. Brandt , S. Capitani , M. Della Morte , D. Djukanovic , J. Gegelia , G. von Hippel , A. Juttner , B. Knippschild , H. B. Meyer , H. Wittig

The relatively small fraction of the spin of the proton carried by its quarks presents a major challenge to our understanding of the strong interaction. Traditional efforts to explore this problem have involved new and imaginative…

Nuclear Theory · Physics 2013-08-09 P. E. Shanahan , A. W. Thomas , K. Tsushima , R. D. Young , F. Myhrer

We report the progress on the lattice QCD calculation of the glue spin contribution to proton spin. This calculation is carried out with valence overlap fermion on 2+1 flavor DWF gauge configurations at two lattice spacings with the…

High Energy Physics - Phenomenology · Physics 2016-03-24 Yi-Bo Yang , Raza Sabbir Sufian , Andrei Alexandru , Terrence Draper , Michael J. Glatzmaier , Keh-Fei Liu

This is a review of recent developments in hadron structure within the framework of Lattice QCD. The main focus is on recent achievements in the evaluation of nucleon quantities, such as the axial charge, electromagnetic form factors, the…

High Energy Physics - Lattice · Physics 2014-11-04 Martha Constantinou

In this brief note insightful remarks are made on the controversy on the decomposition of the proton spin into the spin and orbital angular momenta of quarks and gluons. It is argued that the difference in the perception on the nature of…

General Physics · Physics 2015-03-09 S. C. Tiwari

We review recent progress on lattice calculations of nucleon spin structure, including the parton distribution functions, form factors, generalization parton distributions, and recent developments in lattice techniques.

High Energy Physics - Lattice · Physics 2009-08-24 Huey-Wen Lin

This article reviews our present understanding of the QCD spin structure of the proton. We first outline the proton spin puzzle and its possible resolution in QCD. We then review the present and next generation of experiments to resolve the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Steven D. Bass

The status of lattice calculations of the quark spin, the quark orbital angular momentum, the glue angular momentum and glue spin in the nucleon is summarized. The quark spin calculation is recently carried out from the anomalous Ward…

High Energy Physics - Phenomenology · Physics 2016-03-23 Keh-Fei Liu

The proton is one of the main building blocks of all visible matter in the universe. Among its intrinsic properties are its electric charge, mass, and spin. These emerge from the complex dynamics of its fundamental constituents, quarks and…

We present a calculation of the proton momentum and angular momentum decompositions using overlap fermions on a $2+1$-flavor RBC/UKQCD domain-wall lattice at 0.143 fm with a pion mass of 171 MeV which is close to the physical one. A…

High Energy Physics - Lattice · Physics 2022-08-08 Gen Wang , Yi-Bo Yang , Jian Liang , Terrence Draper , Keh-Fei Liu

Highlights from recent computations in lattice QCD involving baryons are presented. Calculations of the proton mass and spin decompositions are discussed, a percent level determination of the nucleon axial coupling is described, and…

Nuclear Theory · Physics 2019-09-19 Colin Morningstar

Momentum and spatial distributions of quarks and gluons inside hadrons are typically encoded in the so-called generalized parton distributions (GPDs). GPDs are multi-dimensional quantities that are very challenging to extract, both…

The gravitational form factors (GFFs) of a hadron encode fundamental aspects of its structure, including its shape and size as defined from e.g., its energy density. This work presents a determination of the flavor decomposition of the GFFs…

High Energy Physics - Lattice · Physics 2024-06-25 Daniel C. Hackett , Dimitra A. Pefkou , Phiala E. Shanahan

We review progress on hadron structure using lattice QCD simulations at or near to physical values of the QCD parameters. In particular, we discuss recent results on hadron masses, the nucleon charges, spin, gluon and quark unpolarized…

High Energy Physics - Lattice · Physics 2015-12-15 Constantia Alexandrou

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

The QCDSF/UKQCD collaboration has an ongoing program to calculate nucleon matrix elements with two flavours of dynamical O(a) improved Wilson fermions. Here we present recent results on the electromagnetic form factors, the quark momentum…

High Energy Physics - Lattice · Physics 2008-11-26 M. Göckeler , Ph. Hägler , R. Horsley , Y. Nakamura , D. Pleiter , P. E. L. Rakow , A. Schäfer , G. Schierholz , W. Schroers , H. Stüben , J. M. Zanotti

A future Electron-Ion Collider will enable the gluon contributions to the gravitational form factors of the proton to be constrained experimentally for the first time. Here, the first calculation of these form factors from lattice Quantum…

High Energy Physics - Lattice · Physics 2019-01-30 P. E. Shanahan , W. Detmold

This work presents the first calculation in lattice QCD of three moments of spin-averaged and spin-polarized generalized parton distributions in the proton. It is shown that the slope of the associated generalized form factors decreases…

High Energy Physics - Lattice · Physics 2012-08-27 LHPC , SESAM Collaborations , : , Ph. Hagler , J. W. Negele , D. B. Renner , W. Schroers , Th. Lippert , K. Schilling

We calculate the quark orbital angular momentum of the nucleon from the quark energy-momentum tensor form factors on the lattice. The disconnected insertion is estimated stochastically which employs the $Z_2$ noise with an unbiased…

High Energy Physics - Phenomenology · Physics 2016-09-06 N. Mathur , S. J. Dong , K. F. Liu , L. Mankiewicz , N. C. Mukhopadhyay