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We study the nucleon electromagnetic form factors (EM FFs) using a recently developed method combining Chiral Effective Field Theory ($\chi$EFT) and dispersion analysis. The spectral functions on the two-pion cut at $t > 4 M_\pi^2$ are…

High Energy Physics - Phenomenology · Physics 2018-05-16 J. M. Alarcón , C. Weiss

We propose a method for calculating the nucleon form factors (FFs) of $G$-parity-even operators by combining Chiral Effective Field Theory ($\chi$EFT) and dispersion analysis. The FFs are expressed as dispersive integrals over the two-pion…

High Energy Physics - Phenomenology · Physics 2017-11-29 J. M. Alarcón , C. Weiss

We present a high-statistics calculation of nucleon electromagnetic form factors in $N_f=2+1$ lattice QCD using domain wall quarks on fine lattices, to attain a new level of precision in systematic and statistical errors. Our calculations…

The nucleon isovector electromagnetic form factors are calculated up to next-to-next-to-leading order by combining relativistic chiral perturbation theory (ChPT) of pion, nucleon, and $\Delta$(1232) with dispersion theory. We specifically…

High Energy Physics - Phenomenology · Physics 2023-12-18 Fernando Alvarado , Di An , Luis Alvarez-Ruso , Stefan Leupold

Dispersion relations provide a powerful tool to analyse the electromagnetic form factors of the nucleon both in the space-like and time-like regions with constraints from other experiments, unitarity, and perturbative QCD. We give a brief…

High Energy Physics - Phenomenology · Physics 2007-05-23 H. -W. Hammer

We investigate the imaginary parts of the nucleon electromagnetic and axial form factors close to threshold in the framework of heavy baryon chiral perturbation theory. For the isovector electromagnetic form factors, we recover the well…

High Energy Physics - Phenomenology · Physics 2009-10-28 V. Bernard , N. Kaiser , Ulf-G. Meißner

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

The unitarity relations for isovector nucleon form factors in the two-pion approximation for the intermediate states are analytically extended in a model independent way from the real half-axis t > 4 $\mu^2$ ($\mu$ is the pion mass) to the…

Nuclear Theory · Physics 2007-05-23 M. I. Krivoruchenko

The electromagnetic form factors of the nucleon are calculated in an extended chiral constituent-quark model where the effective interaction is described by the exchange of pseudoscalar, vector, and scalar mesons. Two-body current-density…

High Energy Physics - Phenomenology · Physics 2007-05-23 P. Demetriou , S. Boffi , M. Radici , R. F. Wagenbrunn

We present the recent high-statistics calculations of the nucleon electromagnetic form factors with fully dynamical domain wall fermions on the 32^3x64 lattices generated by the RBC and UKQCD collaborations, with pion masses at roughly 297…

High Energy Physics - Lattice · Physics 2010-02-19 M. F. Lin , J. D. Bratt , M. Engelhardt , Ph. Hagler , T. R. Hemmert , H. B. Meyer , J. W. Negele , A. V. Pochinsky , M. Procura , W. Schroers , S. Syritsyn

We review the dispersion-theoretical analysis of the electromagnetic form factors of the nucleon. We emphasize in particular the role of unitarity and analyticity in the construction of the isoscalar and isovector spectral functions. We…

High Energy Physics - Phenomenology · Physics 2021-08-27 Yong-Hui Lin , Hans-Werner Hammer , Ulf-G. Meißner

The electromagnetic form factors have attracted lot of theoretical and experimental attention recently as they encode extensive information on the internal structure of the hadron. An understanding of the form factors is necessary to…

High Energy Physics - Phenomenology · Physics 2011-08-02 Harleen Dahiya , Neetika Sharma

Background: The transverse densities $\rho_{1, 2}(b)$ describe the distributions of electric charge and magnetic moment at fixed light-front time and connect the nucleon's elastic form factors with its partonic structure. The dispersive…

High Energy Physics - Phenomenology · Physics 2022-09-21 J. M. Alarcón , C. Weiss

We calculate the imaginary parts of the isoscalar scalar and isovector electromagnetic form factors of the nucleon up to two-loop order in chiral perturbation theory. Particular attention is paid on the correct behavior of Im $\sigma_N(t)$…

Nuclear Theory · Physics 2009-11-10 N. Kaiser

The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and…

High Energy Physics - Phenomenology · Physics 2008-11-26 P. Wang , D. B. Leinweber , A. W. Thomas , R. D. Young

The electromagnetic form factors of the proton and the neutron in the timelike region are investigated. Electron-positron annihilation into antinucleon-nucleon ($\bar NN$) pairs is treated in distorted wave Born approximation, including the…

Nuclear Theory · Physics 2023-12-06 Qin-He Yang , Ling-Yun Dai , Di Guo , Johann Haidenbauer , Xian-Wei Kang , Ulf-G. Meißner

We present results for the isovector axial, induced pseudoscalar, electric, and magnetic form factors of the nucleon. The calculations were done using $2+1+1$-flavor HISQ ensembles generated by the MILC collaboration with lattice spacings…

High Energy Physics - Lattice · Physics 2018-04-18 Yong-Chull Jang , Tanmoy Bhattacharya , Rajan Gupta , Huey-Wen Lin , Boram Yoon

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…

We compute the electromagnetic form factors of the nucleon in quenched lattice QCD, using non-perturbatively improved Wilson fermions, and compare the results with phenomenology and chiral effective field theory.

High Energy Physics - Lattice · Physics 2010-04-06 M. Göckeler , T. R. Hemmert , R. Horsley , D. Pleiter , P. E. L. Rakow , A. Schäfer , G. Schierholz

The electromagnetic form factors provide important hints for the internal structure of the nucleon and continue to be of major interest for experimentalists. For an intermediate range of momentum transfers the form factors can be calculated…

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