How well do we know the electromagnetic form factors of the proton?

Abstract

Several experiments have extracted proton electromagnetic form factors from elastic cross section measurements using the Rosenbluth technique. Global analyses of these measurements indicate approximate scaling of the electric and magnetic form factors (mu_p*G_E/G_M = 1), in contrast to recent polarization transfer measurements from Jefferson Lab. We present here a global reanalysis of the cross section data aimed at understanding the disagreement between the Rosenbluth extraction and the polarization transfer data. We find that the individual cross section measurements are self-consistent, and that the new global analysis yields results that are still inconsistent with polarization measurements. This discrepancy indicates a fundamental problem in one of the two techniques, or a significant error in polarization transfer or cross section measurements. An error in the polarization data would imply a large error in the extracted electric form factor, while an error in the cross sections implies an uncertainty in the extracted form factors, even if the form factor ratiois measured exactly.

14 pages, 10 figures, submitted to Phys. Rev. C

References in corpus (1)

• Ruling out four-neutrino oscillation interpretations of the LSND anomaly?

Cited by in corpus (113)

• Nucleon Electromagnetic Form Factors
• Proton elastic form factor ratios to $Q^2$ = 3.5 GeV${}^2$ by polarization transfer
• Quest for precision in hadronic cross sections at low energy: Monte Carlo tools vs. experimental data
• Electromagnetic excitation of the Delta(1232)-resonance
• Global analysis of proton elastic form factor data with two-photon exchange corrections
• Precision Rosenbluth measurement of the proton elastic form factors
• A new parameterization of the nucleon elastic form factors
• Two-photon exchange in elastic electron-nucleon scattering
• Nucleon electromagnetic form factors
• Measurements of electron-proton elastic cross sections for $0.4<Q^2<5.5(GeV/c{)}^2$
• Parity-violating electroweak asymmetry in $\vec{e}p$ scattering
• The two-photon exchange contribution to elastic electron-nucleon scattering at large momentum transfer
• Nucleon Form Factors in QCD
• Review of two-photon exchange in electron scattering
• Extraction of the proton radius from electron-proton scattering data
• Electromagnetic Form Factors of the Nucleon and Compton Scattering
• Proton and neutron electromagnetic form factors and uncertainties
• Implications of the discrepancy between proton form factor measurements
• $\Delta$ resonance contribution to two-photon exchange in electron-proton scattering
• Measurement of the two-photon exchange contribution to the elastic $e^{\pm }p$ scattering cross sections at the VEPP-3 storage ring
• Two-photon exchange in elastic electron-proton scattering
• The SAMPLE Experiment and Weak Nucleon Structure
• Re-analysis of the nucleon space- and time-like electromagnetic form factors in a two-component model
• Low Q^2 measurements of the proton form factor ratio $m{u}_p{G}_E/G_M$
• A Precise Measurement of the Neutron Magnetic Form Factor GMn in the Few-GeV2 Region
• Towards a resolution of the proton form factor problem: new electron and positron scattering data
• Evidence for two-photon exchange contributions in electron-proton and positron-proton elastic scattering
• Quasielastic axial-vector mass from experiments on neutrino-nucleus scattering
• Electromagnetic form factors of the nucleon: new fit and analysis of uncertainties
• A pure S-wave covariant model for the nucleon
• All electromagnetic form factors
• Extraction of two-photon contributions to the proton form factors
• Flavor decomposition of the nucleon electromagnetic form factors
• Experimental constraints on non-linearities induced by two-photon effects in elastic and inelastic Rosenbluth separations
• Precise determination of low-Q nucleon electromagnetic form factors and their impact on parity-violating e-p elastic scattering
• Measurement of two-photon exchange effect by comparing elastic $e^{\pm }p$ cross sections
• New Measurements of the Transverse Beam Asymmetry for Elastic Electron Scattering from Selected Nuclei
• Perturbative QCD predictions for two-photon exchange
• Nucleon form factors, B-meson factories and the radiative return
• Search for evidence of two photon contribution in elastic electron proton data
• Improved Light-Cone Sum Rules for the Electromagnetic Form Factors of the Nucleon
• Dispersion-theoretical analysis of the electromagnetic form factors of the nucleon: Past, present and future
• Distribution amplitudes of $\Sigma$ and $\Lambda$ and their electromagnetic form factors
• Phenomenological analysis of two-photon exchange effects in proton form factor measurements
• Two photon exchange amplitude with πN intermediate states: P33 channel
• Nucleon Form Factors - A Jefferson Lab Perspective
• Reexamination of phenomenological two-photon exchange corrections to the proton form factors and e+-p scattering
• The Nucleon Distribution Amplitudes and their application to nucleon form factors and the $N\to \Delta$ transition at intermediate values of $Q^2$
• Coulomb distortion in high-Q^2 elastic e-p scattering
• $\Delta (1232)$ Resonance Contribution to Two-Photon Exchange in Electron-Proton Scattering Revisited
• Phenomenological Lagrangian approach to the electromagnetic deuteron form factors
• Comparison of Neural Network and Hadronic Model Predictions of Two-Photon Exchange Effect
• Polarization effects in the reaction $\bar{p}+p\to e^{+}+e^{-}$ in presence of two-photon exchange
• Measurement of the Target-Normal Single-Spin Asymmetry in Quasi-Elastic Scattering from the Reaction ${}^3$He${}^{\uparrow }(e,e^{\prime })$
• Tensor Correlations Measured in 3He(e,e'pp)n
• Form Factors and Two-Photon Exchange in High-Energy Elastic Electron-Proton Scattering
• Measurement of the Target-Normal Single-Spin Asymmetry in Deep-Inelastic Scattering from the Reaction ${}^3{\mathrm{He}}^{\uparrow }(e,e^{\prime })X$
• Reanalysis of Rosenbluth measurements of the proton form factors
• Vector and Axial Form Factors Applied to Neutrino Quasielastic Scattering
• Demonstration of a novel technique to measure two-photon exchange effects in elastic $e^{\pm }p$ scattering
• Two-Photon Exchange Effect Studied with Neural Networks
• A description of the ratio between electric and magnetic proton form factors by using space-like, time-like data and dispersion relations
• Two-Photon Exchange Contribution to Proton Form Factors in Time-Like region
• Two-photon exchange effect on deuteron electromagnetic form factors
• Lepton-Proton Two-Photon Exchange in Chiral Perturbation Theory
• Two-photon exchange and elastic scattering of electrons/positrons on the proton. (Proposal for an experiment at VEPP-3)
• Comparison of Nucleon Form Factors from Lattice QCD Against the Light Front Cloudy Bag Model and Extrapolation to the Physical Mass Regime
• Model-independent extraction of two-photon effects in elastic electron-proton scattering
• Phenomenological extraction of two-photon exchange amplitudes from elastic electron-proton scattering cross section data
• Nucleon Form Factors to Next-to-Leading Order with Light-Cone Sum Rules
• Nucleon form factors and final state radiative corrections to $e^{+}{e}^{-}\to \bar{p}p\gamma$
• On radiative corrections for unpolarized electron proton elastic scattering
• Neural Network Parameterizations of Electromagnetic Nucleon Form Factors
• Light-cone QCD Sum Rules for the $\Lambda$ Baryon Electromagnetic Form Factors and its magnetic moment
• Observables in elastic electron-deuteron scattering with two-photon exchange
• Two-photon-exchange effects in the electro-excitation of the $\Delta$ resonance
• How much two-photon exchange is needed to resolve the proton form factor discrepancy?
• Eikonal zeros in the momentum transfer space from proton-proton scattering: An empirical analysis
• Ratio of ${\sigma }_L/{\sigma }_T$ for $p(e,e^{\prime }{K}^{+})\Lambda$ Extracted from Polarization Transfer
• Delta(1232) contribution to real photon radiative corrections for elastic electron-proton scattering
• Two-photon exchange corrections to ${\gamma }^{\ast }N\Delta$ form factors for $Q^2\le 4$ (Gev/$c$)${}^2$
• Electromagnetic form factors of ${\Lambda }_b$ in the Bethe-Salpeter equation approach
• Electromagnetic nucleon form factors from QCD sum rules
• Radiative and chiral corrections to elastic lepton-proton scattering in chiral perturbation theory
• Up- and Down-Quark Contributions to the Nucleon Form Factors
• Estiamte of the two-photon exchange effect on deuteron electromagnetic form factors
• Updated analysis of recent results on electron and positron elastic scattering on proton
• Form factor ratio from unpolarized elastic electron proton scattering
• Two photon exchange in elastic electron scattering off hadronic systems
• Target Normal Spin Asymmetry of the Elastic ep-Scattering at Resonance Energy
• On radiative corrections to polarization observables in electron-proton scattering
• Two-photon exchange: myth and history
• Magnetization screening from gluonic currents and scaling law violation in the ratio of magnetic form factors for neutron and proton
• Timelike and spacelike hadron form factors, Fock state components and light-front dynamics
• Electromagnetic nucleon form factors in the extended vector meson dominance model
• Spin rotation as an element of polarization experiments on elastic electron-proton scattering
• Electromagnetic form factors and polarizations of non-Dirac particles with rest spin 1/2
• Improved radiative corrections and proton charge form factor from the Rosenbluth separation technique
• Improved radiative corrections for (e,e'p) experiments - A novel approach to multi-photon bremsstrahlung
• Sea contribution to the charge radii and quadrupole moment of $J^P={\frac{1}{2}}^{+},{\frac{3}{2}}^{+}$ baryons
• Inclusive scattering data on light nuclei as a precision tool for the extraction of G_M^n
• Two-Boson Exchange Physics: A Brief Review
• Impact of new particles on the ratio of Electromagnetic form factors
• The Nucleon Elastic Form Factors
• Ratio of the proton electromagnetic form factors from meson dressing
• Overview of nucleon structure studies
• Electromagnetic form factors of ${\Lambda }_c$ in the Bethe-Salpeter equation approach
• A measurement of two-photon exchange in Super-Rosenbluth separations with positron beams
• Super-Rosenbluth Measurements with Electrons and Positrons
• A comparison of forward and backward pp pair knockout in 3He(e,e'pp)n
• Magnetic moment operator of non-Dirac particles and some elements of polarization $ep$-experiments
• Unpolarized nucleon structure studies utilizing polarized electromagnetic probes
• Two-photon contributions to the Rosenbluth cross-section in the Skyrme model