Nucleon electromagnetic form factors

Arrington, J.; Roberts, C. D.; Zanotti, J. M.

doi:10.1088/0954-3899/34/7/s03

Cited by 242 publications

(276 citation statements)

References 238 publications

(429 reference statements)

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“…Since the publication of the JLab ratio measurements, there have been two review papers on the subject of nucleon e.m. FFs [Gao03,Hyd04], with a third one just recently completed [Arr06]. The present review complements the previous ones by bringing the experimental situation up-to-date, and gives an overview of the latest theoretical developments to understand the nucleon e.m. FFs from the underlying theory of the strong interactions, Quantum Chromodynamics (QCD).…”

Section: Introductionmentioning

confidence: 73%

Nucleon electromagnetic form factors

Perdrisat

Punjabi

Vanderhaeghen

2007

Progress in Particle and Nuclear Physics

461

582

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There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has been greatly improved by performing double polarization experiments, in comparison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at MIT-Bates, MAMI, and JLab. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed, including the recent progress in the determination of the valence quark generalized parton distributions of the nucleon, as well as the steady rate of improvements made in the lattice QCD calculations.

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Section: Introductionmentioning

confidence: 73%

Nucleon electromagnetic form factors

Perdrisat

Punjabi

Vanderhaeghen

2007

Progress in Particle and Nuclear Physics

461

582

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“…Naturally, our own bias is towards the Dyson-Schwinger/Bethe-Salpeter approach and therefore we will mainly concentrate on pointing out its connections with other methods and the inherent similarities and differences. We apologize to those colleagues whose work is not mentioned here; for more comprehensive discussions we refer to the existing reviews focusing on nucleon spacelike electromagnetic form factors [440][441][442][443][444][445][446], axial form factors [447,448], transition form factors [11][12][13][14], and timelike form factors [445,449].…”

Section: Methodological Overviewmentioning

confidence: 99%

“…Nucleon form factor calculations in lattice QCD have made substantial progress in recent years. Whereas the early quenched calculations are summarized in the review articles [442,450], nowadays essentially all calculations are performed using dynamical fermions. Studies of electromagnetic nucleon form factors are available from various collaborations for N f = 2 [451][452][453][454][455], N f = 2 + 1 [397,[456][457][458][459][460][461][462] and N f = 2 + 1 + 1 flavours [463,464], including calculations nearly at the physical pion mass [397] which agree reasonably well with the experimental data.…”

Section: Methodological Overviewmentioning

confidence: 99%

Baryons as relativistic three-quark bound states

Eichmann

Sanchis-Alepuz

Williams

et al. 2016

Progress in Particle and Nuclear Physics

406

529

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We review the spectrum and electromagnetic properties of baryons described as relativistic three-quark bound states within QCD. The composite nature of baryons results in a rich excitation spectrum, whilst leading to highly non-trivial structural properties explored by the coupling to external (electromagnetic and other) currents. Both present many unsolved problems despite decades of experimental and theoretical research. We discuss the progress in these fields from a theoretical perspective, focusing on nonperturbative QCD as encoded in the functional approach via Dyson-Schwinger and Bethe-Salpeter equations. We give a systematic overview as to how results are obtained in this framework and explain technical connections to lattice QCD. We also discuss the mutual relations to the quark model, which still serves as a reference to distinguish 'expected' from 'unexpected' physics. We confront recent results on the spectrum of non-strange and strange baryons, their form factors and the issues of two-photon processes and Compton scattering determined in the DysonSchwinger framework with those of lattice QCD and the available experimental data. The general aim is to identify the underlying physical mechanisms behind the plethora of observable phenomena in terms of the underlying quark and gluon degrees of freedom.

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“…The ratio can be extracted in a similar fashion using polarized beams and targets by measuring the asymmetry for two different spin directions [3,4]. The two methods yield strikingly different results, with values of µ p G p E /G p M differing almost by a factor of three at high Q 2 .…”

Section: B Recoil Polarization Measurementsmentioning

confidence: 99%

Flavor decomposition of the nucleon electromagnetic form factors at lowQ2

2015

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Background The spatial distribution of charge and magnetization within the proton is encoded in the elastic form factors.These have been precisely measured in elastic electron scattering, and the combination of proton and neutron form factors allows for the separation of the up-and down-quark contributions.Purpose In this work, we extract the proton and neutron form factors from world's data with an emphasis on precise new data covering the low-momentum region, which is sensitive to the large-scale structure of the nucleon. From these, we separate the up-and down-quark contributions to the proton form factors.Method We combine cross section and polarization measurements of elastic electron-proton scattering to separate the proton form factors and two-photon exchange (TPE) contributions. We combine the proton form factors with parameterization of the neutron form factor data and uncertainties to separate the up-and down-quark contributions to the proton's charge and magnetic form factors.Results The extracted TPE corrections are compared to previous phenomenological extractions, TPE calculations, and direct measurements from the comparison of electron and positron scattering. The flavor-separated form factors are extracted and compared to models of the nucleon structure.Conclusions With the inclusion of the precise new data, the extracted TPE contributions show a clear change of sign at low Q 2 , necessary to explain the high-Q 2 form factor discrepancy while being consistent with the known Q 2 → 0 limit. We find that the new Mainz data yield a significantly different result for the proton magnetic form factor and its flavorseparated contributions. We also observe that the RMS radius of both the up-and down-quark distributions are smaller than the RMS charge radius of the proton.

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Nucleon electromagnetic form factors

Cited by 242 publications

References 238 publications

Nucleon electromagnetic form factors

Nucleon electromagnetic form factors

Baryons as relativistic three-quark bound states

Flavor decomposition of the nucleon electromagnetic form factors at lowQ2

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