The structure function method applied to polarized and unpolarized electron-proton scattering: a solution of the G_E(p)/G_M(p) discrepancy

Abstract

The cross section for polarized and unpolarized electron-proton scattering is calculated taking into account radiative corrections in leading and next-to leading logarithmic approximation. The expression of the cross section is formally similar to the cross section of the Drell-Yan process, where the structure functions of the electron play the role of Drell-Yan probability distributions. The interference of the Born amplitude with the two photon exchange amplitude (box-type diagrams) is expressed as a contribution to K-factor and it is larger when the momentum is equally shared between the two photons, assuming that proton form factors decrease rapidly with the momentum transfer squared. The calculation of the box amplitude is done when the intermediate state is a proton or the Delta-resonance. The results of numerical estimations show that the present calculation of radiative corrections can bring into agreement the conflicting experimental results on proton electromagnetic form factors an that the two photon contribution is very small.

22 pages, 8 figures, revision of two-photon exchange K-factor calculation

References in corpus (15)

• The ratio of proton's electric to magnetic form factors measured by polarization transfer
• Measurement of GEp/GMp in ep -> ep to Q2 = 5.6 GeV2
• Proton elastic form factor ratios to $Q^2$ = 3.5 GeV${}^2$ by polarization transfer
• Precision Rosenbluth measurement of the proton elastic form factors
• Two-photon exchange in elastic electron-nucleon scattering
• Measurements of electron-proton elastic cross sections for $0.4<Q^2<5.5(GeV/c{)}^2$
• Electroproduction of the Delta Resonance at High Momentum Transfer
• Radiative Corrections to Electron-Proton Scattering
• The two-photon exchange contribution to elastic electron-nucleon scattering at large momentum transfer
• $\Delta$ resonance contribution to two-photon exchange in electron-proton scattering
• Search for evidence of two photon contribution in elastic electron proton data
• Model independent radiative corrections in processes of polarized electron-nucleon elastic scattering
• Target normal spin asymmetry and charge asymmetry for $e\mu$ elastic scattering and the crossed processes
• Radiative Correction to the Transferred Polarization in Elastic Electron-Proton Scattering
• High energy inelastic electron hadron scattering, in peripheral kinematics. Sum rules for hadron form factors

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• Polarization Transfer Observables in Elastic Electron Proton Scattering at $Q^2=$2.5, 5.2, 6.8, and 8.5 GeV${}^2$
• Time- and Spacelike Nucleon Electromagnetic Form Factors beyond Relativistic Constituent Quark Models
• Nucleon Form Factors - A Jefferson Lab Perspective
• A new event generator for the elastic scattering of charged leptons on protons
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• Feasibility studies of the time-like proton electromagnetic form factor measurements with PANDA at FAIR
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• Comparison of Neural Network and Hadronic Model Predictions of Two-Photon Exchange Effect
• Reanalysis of Rosenbluth measurements of the proton form factors
• Models of parton distributions and the description of form factors of nucleon
• Phenomenological extraction of two-photon exchange amplitudes from elastic electron-proton scattering cross section data
• Charge asymmetry for electron (positron)-proton elastic scattering at large angle
• On radiative corrections for unpolarized electron proton elastic scattering
• Radiative corrections for electron proton elastic scattering taking into account high orders and hard photon emission
• Updated analysis of recent results on electron and positron elastic scattering on proton
• Estiamte of the two-photon exchange effect on deuteron electromagnetic form factors
• Measurement of the Charge-Averaged Elastic Lepton-Proton Scattering Cross Section by the OLYMPUS Experiment
• Form factor ratio from unpolarized elastic electron proton scattering
• Rosenbluth Nonlinearity from Two-Photon Exchange
• Radiative corrections to DVCS electron tensor
• Two-photon exchange: myth and history
• General analysis of two--photon exchange in elastic electron--${}^{4}He$ scattering and $e^{+}+e^{-}\to {\pi }^{+}+{\pi }^{-}.$
• Measuring the lepton sign asymmetry in elastic electron-proton scattering with OLYMPUS
• Disperon QED
• Radiative corrections in nucleon time-like form factors measurements
• Impact of new particles on the ratio of Electromagnetic form factors
• Logarithmic corrections and soft photon phenomenology in the multipole model of the nucleon form factors
• Radiative corrections in proton--antiproton annihilation to electron-positron and their application to the PANDA experiment