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We present a quenched lattice QCD calculation of the first few moments of the polarized and un-polarized structure functions of the nucleon. Our calculations are done using domain wall fermions and the DBW2 gauge action with inverse lattice…

High Energy Physics - Lattice · Physics 2011-08-11 Kostas Orginos , Thomas Blum , Shigemi Ohta

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

The nucleon distribution amplitudes and the nucleon-to-pion transition distribution amplitudes are investigated at leading twist within the frame of a light-cone quark model. The distribution amplitudes probe the three-quark component of…

High Energy Physics - Phenomenology · Physics 2010-05-28 B. Pasquini , M. Pincetti , S. Boffi

A complete description of the nucleon structure in terms of generalized parton distributions (GPDs) at twist 2 level requires the measurement/computation of the eight functions H, E, \tilde H, \tilde E, H_T, E_T, \tilde H_T and \tilde E_T,…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ph. Hagler , J. W. Negele , D. B. Renner , W. Schroers , T. Lippert , K. Schilling

We present the first high-twist study of the proton form factors $F_{1,2}(Q^2)$ in $ep$ elastic scattering based on the perturbative QCD $k_T$ factorization, $Q^2$ being momentum transfer squared. It is motivated by unexpectedly large…

High Energy Physics - Phenomenology · Physics 2025-12-05 Ji-Xin Yu , Shan Cheng , Jia-Jie Han , Hsiang-nan Li , Fu-Sheng Yu

This work applies lattice QCD to compute quark momentum distributions in the nucleon. We explore a novel approach based on non-local operators in order to analyze transverse momentum dependent parton distribution functions, which encode…

High Energy Physics - Lattice · Physics 2009-07-15 Bernhard U. Musch

We calculate the non-forward quark matrix elements for operators with two covariant derivatives in one-loop lattice perturbation theory using Wilson fermions. These matrix elements are needed in the renormalisation of the second moment of…

High Energy Physics - Lattice · Physics 2008-11-26 M. Göckeler , R. Horsley , H. Perlt , P. E. L. Rakow , A. Schäfer , G. Schierholz , A. Schiller

We investigate scalar matrix elements of the nucleon using $N_f=2+1+1$ flavors of maximally twisted mass fermions at a fixed value of the lattice spacing of $a\approx 0.078{\rm fm}$. We compute disconnected contributions to the relevant…

High Energy Physics - Lattice · Physics 2012-02-17 S. Dinter , V. Drach , K. Jansen

We update the leading order in $\alpha_s$ QCD amplitude for deep exclusive neutrino and antineutrino production of a light meson on an unpolarized nucleon. The factorization theorems of the collinear QCD approach allow us to write the…

High Energy Physics - Phenomenology · Physics 2017-07-05 B. Pire , L. Szymanowski , J. Wagner

This work presents a determination of potential short-distance contributions to the unphysical $\pi^-\rightarrow\pi^+ e^- e^-$ decay through lattice QCD calculations. The hadronic contributions to the transition amplitude are described by…

High Energy Physics - Lattice · Physics 2023-05-17 William Detmold , William I. Jay , David J. Murphy , Patrick R. Oare , Phiala E. Shanahan

The nuclear matrix element determining the $pp\to d e^+ \nu$ fusion cross section and the Gamow-Teller matrix element contributing to tritium $\beta$-decay are calculated with lattice Quantum Chromodynamics (QCD) for the first time. Using a…

We present the results of a lattice study of the normalization constants and second moments of the light-cone distribution amplitudes of longitudinally and transversely polarized $\rho$ mesons. The calculation is performed using two flavors…

This paper is devoted to the study of the leading twist distribution amplitudes of P-wave nonrelativistic mesons. It is shown that at the leading order approximation in relative velocity of quark-antiquark pair inside the mesons these…

High Energy Physics - Phenomenology · Physics 2009-04-22 V. V. Braguta , A. K. Likhoded , A. V. Luchinsky

We describe the present status of the pion distribution amplitude (DA) as it originates from several sources: (i) a nonperturbative approach based on QCD sum rules with nonlocal condensates, (ii) an $O(\alpha_s)$ QCD analysis of the CLEO…

High Energy Physics - Phenomenology · Physics 2009-04-17 A. P. Bakulev , S. V. Mikhailov , A. V. Pimikov , N. G. Stefanis

We review the calculation of moments of both the polarized and unpolarized parton distribution functions of the nucleon in lattice QCD, and in particular their extrapolation to the physical region. We also discuss the reconstruction of the…

High Energy Physics - Lattice · Physics 2008-11-26 W. Detmold , W. Melnitchouk , A. W. Thomas

We present lattice-QCD results on the nucleon isovector axial, scalar and tensor charges, the isovector electromagnetic Dirac and Pauli form factors, and the connected parts of the isoscalar charges. The calculations have been done using…

High Energy Physics - Lattice · Physics 2014-05-14 Tanmoy Bhattacharya , Saul D. Cohen , Rajan Gupta , Anosh Joseph , Huey-Wen Lin , Boram Yoon

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…

High Energy Physics - Lattice · Physics 2021-11-24 Joseph Karpie , Kostas Orginos , Anatoly Radyushkin , Savvas Zafeiropoulos

We present results for the nucleon's leading-twist spin-independent valence parton distribution functions obtained from a theoretical framework based on the Dyson-Schwinger equations (DSEs) of QCD that previously gave an excellent…

Nuclear Theory · Physics 2018-08-01 Kyle D. Bednar , Ian C. Cloët , Peter C. Tandy

The light-cone distribution amplitudes (LCDAs) serve as important non-perturbative inputs for the study of hard exclusive processes. In this paper, we calculate ten LCDAs at twist-2 for the S-wave and P-wave $B_c$ mesons up to the…

High Energy Physics - Phenomenology · Physics 2016-08-24 Ji Xu , Deshan Yang

We present a lattice computation of the first moment of the kaon's leading-twist distribution amplitude. We use ensembles with 2+1 dynamical flavours of domain wall fermions and the Iwasaki gauge action from the RBC and UKQCD joint dataset.…

High Energy Physics - Lattice · Physics 2009-10-09 P. A. Boyle , M. A. Donnellan , J. M. Flynn , A. Juttner , J. Noaki , C. T. Sachrajda , R. J. Tweedie