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Related papers: Nucleon Axial Form Factor from Lattice QCD

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We present results for the non-perturbative determination of the improvement and renormalization factors of the isovector axial current for lattice QCD with two flavors of dynamical Wilson quarks. The improvement and normalization…

High Energy Physics - Lattice · Physics 2007-05-23 Roland Hoffmann , Michele Della Morte , Francesco Knechtli , Rainer Sommer , Ulli Wolff

There is a long-standing discrepancy between different measurements of the electric and magnetic radii of the proton. Lattice QCD calculations are a well-suited tool for theoretical investigations of the structure of the nucleon from first…

High Energy Physics - Lattice · Physics 2024-05-24 Dalibor Djukanovic , Georg von Hippel , Harvey B. Meyer , Konstantin Ottnad , Miguel Salg , Hartmut Wittig

We determine the $u$ and $d$ quark contributions to the proton magnetic form factor at finite momentum transfer by applying chiral corrections to quenched lattice data. Heavy baryon chiral perturbation theory is applied at next to leading…

High Energy Physics - Phenomenology · Physics 2010-02-17 P. Wang , D. B. Leinweber , A. W. Thomas , R. D. Young

The theoretical and experimental status of the isovector axial-vector current form factors G_A(q^2) and G_P(q^2) of the nucleon is reviewed. We also describe a new calculation of these form factors in manifestly Lorentz-invariant chiral…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. R. Schindler , S. Scherer

We present results for the isovector electromagnetic form factors of the nucleon computed on the CLS ensembles with $N_f=2+1$ flavors of $\mathcal{O}(a)$-improved Wilson fermions and an $\mathcal{O}(a)$-improved vector current. The analysis…

High Energy Physics - Lattice · Physics 2021-06-02 D. Djukanovic , T. Harris , G. von Hippel , P. M. Junnarkar , H. B. Meyer , D. Mohler , K. Ottnad , T. Schulz , J. Wilhelm , H. Wittig

We present results on the nucleon axial vector form factors $G_A(q^2)$ and $G_p(q^2)$ in the quenched theory and using two degenerate flavors of dynamical Wilson fermions for momentum transfer squared from about 0.1 to about 2 GeV^2 and for…

High Energy Physics - Lattice · Physics 2008-11-26 C. Alexandrou , G. Koutsou , Th. Leontiou , J. W. Negele , A. Tsapalis

We present our progress on the computation of the axial form factor of the nucleon with flavour structure $u+d-2s$ from lattice QCD. We employ a set of $N_f=2+1$ CLS ensembles with $O(a)$-improved Wilson fermions and the L\"uscher-Weisz…

We present the analysis of isovector axial vector nucleon form factors on a set of $N_f=2+1$ CLS ensembles with $\mathcal O(a)$-improved Wilson fermions and L\"uscher-Weisz gauge action. The set of ensembles covers a pion mass range of…

High Energy Physics - Lattice · Physics 2021-12-02 Dalibor Djukanovic , Georg von Hippel , Jonna Koponen , Harvey B. Meyer , Konstantin Ottnad , Tobias Schulz , Hartmut Wittig

Vector and axial form factors in the quark resonance model are analyzed with a combination of theoretical and phenomenological arguments. The new form of form factors is deduced from $\Delta$(1232) excitation models and available data. The…

High Energy Physics - Phenomenology · Physics 2014-11-18 K. M. Graczyk , J. T. Sobczyk

We evaluate the nucleon axial form factor, $G_A(q^2)$, and induced pseudoscalar form factor, $G_p(q^2)$, as well as the pion-nucleon form factor, $G_{\pi N N}(q^2)$, in lattice QCD. We also evaluate the corresponding nucleon to $\Delta$…

High Energy Physics - Lattice · Physics 2014-11-18 C. Alexandrou , G. Koutsou , Th. Leontiou , J. W. Negele , A. Tsapalis

We present high statistics results for the isovector nucleon charges and form factors using seven ensembles of 2+1-flavor Wilson-clover fermions. The axial and pseudoscalar form factors obtained on each ensemble satisfy the PCAC relation…

High Energy Physics - Lattice · Physics 2022-03-23 Sungwoo Park , Rajan Gupta , Boram Yoon , Santanu Mondal , Tanmoy Bhattacharya , Yong-Chull Jang , Bálint Joó , Frank Winter

We evaluate the isovector nucleon electromagnetic form factors in quenched and full QCD on the lattice using Wilson fermions. In the quenched theory we use a lattice of spatial size 3 fm at beta=6.0 enabling us to reach low momentum…

High Energy Physics - Lattice · Physics 2008-11-26 C. Alexandrou , G. Koutsou , J. W. Negele , A. Tsapalis

We report on a lattice QCD calculation of the flavor-singlet axial coupling constant $g_A$ of the proton from the axial-vector current. The simulation is carried out at $\beta = 6$ on a quenched $16^3 \times 24$ lattice. An extrapolation to…

High Energy Physics - Phenomenology · Physics 2016-09-01 S. J. Dong , J. -F. Lagae , K. F. Liu

We present preliminary results on the axial form factor $G_A(Q^2)$ and the induced pseudoscalar form factor $G_P(Q^2)$ of the nucleon. A systematic analysis of the excited-state contributions to form factors is performed on the CLS ensemble…

High Energy Physics - Lattice · Physics 2014-11-24 P. M. Junnarkar , S. Capitani , D. Djukanovic , G. von Hippel , J. Hua , B. Jäger , H. B. Meyer , T. D. Rae , H. Wittig

We present results on the electroweak form factors and on the lower moments of parton distributions of the nucleon, within lattice QCD using two dynamical flavors of degenerate twisted mass fermions. Results are obtained on lattices with…

High Energy Physics - Lattice · Physics 2012-01-04 C. Alexandrou , M. Brinet , J. Carbonell , M. Constantinou , P. Guichon , P. A. Harraud , K. Jansen , C. Kallidonis , T. Korzec , M. Papinutto

We present the isovector axial, induced pseudoscalar, and pseudoscalar form factors of the nucleon using three twisted-mass fermion ensembles with degenerate up- and down-, strange-, and charm-quarks with masses tuned to their physical…

We present results for the nucleon electromagnetic form factors using an ensemble of maximally twisted mass clover-improved fermions with pion mass of about 130 MeV. We use multiple sink-source separations and three analysis methods to…

In this article, we calculate the scalar form-factor of the proton in the framework of the light-cone QCD sum rules approach with the three valence quark light-cone distribution amplitudes up to twist-6, and observe the scalar form-factor…

High Energy Physics - Phenomenology · Physics 2009-11-11 Zhi-Gang Wang , Shao-Long Wan , Wei-Min Yang

We report isovector form factors and low moments of structure functions of nucleon in numerical lattice quantum chromodynamics (QCD) from the on-going calculations by the RIKEN-BNL-Columbia (RBC) and UKQCD Collaborations with (2+1)…

High Energy Physics - Lattice · Physics 2012-08-27 UKQCD Collaboration , Takeshi Yamazaki , Shigemi Ohta

A covariant quark model, based both on the spectator formalism and on vector meson dominance, and previously calibrated by the physical data, is here extended to the unphysical region of the lattice data by means of one single extra…

High Energy Physics - Phenomenology · Physics 2010-04-30 G. Ramalho , M. T. Pena