Two-Photon Physics in Hadronic Processes

Abstract

Two-photon exchange contributions to elastic electron-scattering are reviewed. The apparent discrepancy in the extraction of elastic nucleon form factors between unpolarized Rosenbluth and polarization transfer experiments is discussed, as well as the understanding of this puzzle in terms of two-photon exchange corrections. Calculations of such corrections both within partonic and hadronic frameworks are reviewed. In view of recent spin-dependent electron scattering data, the relation of the two-photon exchange process to the hyperfine splitting in hydrogen is critically examined. The imaginary part of the two-photon exchange amplitude as can be accessed from the beam normal spin asymmetry in elastic electron-nucleon scattering is reviewed. Further extensions and open issues in this field are outlined.

Review prepared for Annual Review of Nuclear and Particle Science; 41 pages, 21 figures

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• A unitary isobar model for pion photo- and electroproduction on the proton up to 1 GeV
• Precision physics of simple atoms: QED tests, nuclear structure and fundamental constants
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• Nucleon Form Factors from Generalized Parton Distributions
• Precision Rosenbluth measurement of the proton elastic form factors
• Measurements of the $Q^2$-Dependence of the Proton and Neutron Spin Structure Functions g1p and g1n
• Dispersion relations in real and virtual Compton scattering
• Partonic calculation of the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer
• Generalized parton distributions from nucleon form factor data
• Two-photon exchange in elastic electron-nucleon scattering
• Nucleon electromagnetic form factors
• Measurements of electron-proton elastic cross sections for $0.4<Q^2<5.5(GeV/c{)}^2$
• Radiative Corrections to Electron-Proton Scattering
• The two-photon exchange contribution to elastic electron-nucleon scattering at large momentum transfer
• Precision Measurement of the Proton and Deuteron Spin Structure Functions g2 and Asymmetries A2
• Electromagnetic Form Factors of the Nucleon and Compton Scattering
• $\Delta$ resonance contribution to two-photon exchange in electron-proton scattering
• Measurement of the vector analyzing power in elastic electron-proton scattering as a probe of double photon exchange amplitudes
• New empirical fits to the proton electromagnetic form factors
• Measurement of the Transverse Beam Spin Asymmetry in Elastic Electron Proton Scattering and the Inelastic Contribution to the Imaginary Part of the Two-Photon Exchange Amplitude
• Evidence for two-photon exchange contributions in electron-proton and positron-proton elastic scattering
• Proton radii and two-photon exchange
• Model independent properties of two-photon exchange in elastic electron proton scattering
• Measurement of the Proton Spin Structure Function $g_1(x,Q^2)$ for $Q^2$ from 0.15 to 1.6 GeV${}^2$ with CLAS
• 2S Hyperfine splitting of muonic hydrogen
• Box diagram in the elastic electron-proton scattering
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• Zemach Moments for Hydrogen and Deuterium
• Experimental constraints on non-linearities induced by two-photon effects in elastic and inelastic Rosenbluth separations
• Nuclear Structure-Dependent Radiative Corrections to the Hydrogen Hyperfine Splitting
• Resonance estimates for single spin asymmetries in elastic electron-nucleon scattering
• Contribution of spin 1/2 and 3/2 resonances to two-photon exchange effects in elastic electron-proton scattering
• Leading and higher twists in the proton polarized structure function at large Bjorken x
• Beam normal spin asymmetry in elastic lepton-nucleon scattering
• Zemach and magnetic radius of the proton from the hyperfine splitting in hydrogen
• Collinear Photon Exchange in the Beam Normal Polarization Asymmetry of Elastic Electron-Proton Scattering
• Proton polarizability contribution to the hyperfine splitting in muonic hydrogen
• Two-Photon-Exchange Correction to Parity-Violating Elastic Electron-Proton Scattering
• Measurement of Inclusive Spin Structure Functions of the Deuteron
• Dispersive contributions to $e^{+}p/e^{-}p$ cross section ratio in forward regime
• What do we actually know on the proton radius ?
• New experimental constraints on polarizability corrections to hydrogen hyperfine structure
• The Vector Analyzing Power in Elastic Electron-Proton Scattering
• Doubly virtual Compton scattering and the beam normal spin asymmetry
• Observables in elastic electron-deuteron scattering with two-photon exchange
• Two-photon-exchange effects in the electro-excitation of the $\Delta$ resonance
• Comment on "Constraints on proton structure from precision atomic physics measurements"
• Proton polarizability effect in the hyperfine splitting of the hydrogen atom
• Jefferson Lab's results on the Q^2-evolution of moments of spin structure functions

Cited by in corpus (97)

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• Extraction of the proton radius from electron-proton scattering data
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• The proton charge radius
• 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
• Low Q^2 measurements of the proton form factor ratio $m{u}_p{G}_E/G_M$
• Towards a resolution of the proton form factor problem: new electron and positron scattering data
• Search for effects beyond the Born approximation in polarization transfer observables in $\vec{e}p$ elastic scattering
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• Electromagnetic form factors of the nucleon: new fit and analysis of uncertainties
• A pure S-wave covariant model for the nucleon
• Two-photon exchange in elastic electron-proton scattering : QCD factorization approach
• Model-dependence of the $\gamma Z$ dispersion correction to the parity-violating asymmetry in elastic $ep$ scattering
• Flavor decomposition of the nucleon electromagnetic form factors
• Subtracted dispersion relation formalism for the two-photon exchange correction to elastic electron-proton scattering: comparison with data
• Measurement of two-photon exchange effect by comparing elastic $e^{\pm }p$ cross sections
• Time- and Spacelike Nucleon Electromagnetic Form Factors beyond Relativistic Constituent Quark Models
• New Measurements of the Transverse Beam Asymmetry for Elastic Electron Scattering from Selected Nuclei
• A dispersive approach to two-photon exchange in elastic electron-proton scattering
• Determination of two-photon exchange amplitudes from elastic electron-proton scattering data
• Two-photon exchange corrections to elastic electron-proton scattering at large momentum transfer within the SCET approach
• Two-photon exchange correction in elastic unpolarized electron-proton scattering at small momentum transfer
• Hadron structure at low Q^2
• Nucleon Form Factors - A Jefferson Lab Perspective
• Two-photon exchange contribution to elastic $e^{-}$-proton scattering: Full dispersive treatment of $\pi N$ states and comparison with data
• Effective field theory for large logarithms in radiative corrections to electron proton scattering
• Reexamination of phenomenological two-photon exchange corrections to the proton form factors and e+-p scattering
• A new event generator for the elastic scattering of charged leptons on protons
• Parity Violation in Elastic Electron-Nucleon Scattering: Strangeness Content in the Nucleon
• Review of experimental and theoretical status of the proton radius puzzle
• Feasibility studies of the time-like proton electromagnetic form factor measurements with PANDA at FAIR
• $\Delta (1232)$ Resonance Contribution to Two-Photon Exchange in Electron-Proton Scattering Revisited
• Comparison of Neural Network and Hadronic Model Predictions of Two-Photon Exchange Effect
• Measurement of the Target-Normal Single-Spin Asymmetry in Deep-Inelastic Scattering from the Reaction ${}^3{\mathrm{He}}^{\uparrow }(e,e^{\prime })X$
• Measurement of the Target-Normal Single-Spin Asymmetry in Quasi-Elastic Scattering from the Reaction ${}^3$He${}^{\uparrow }(e,e^{\prime })$
• Charge asymmetry in elastic scattering of massive leptons on protons
• The Role of Mesons in the Electromagnetic Form Factors of the Nucleon
• Forward two-photon exchange in elastic lepton-proton scattering and hyperfine-splitting correction
• Nucleon resonances in Compton scattering
• Demonstration of a novel technique to measure two-photon exchange effects in elastic $e^{\pm }p$ scattering
• Two-photon exchange corrections to elastic $e^{-}$-proton scattering: Full dispersive treatment of $\pi N$ states at low momentum transfers
• Measurements of the Separated Longitudinal Structure Function F_L from Hydrogen and Deuterium Targets at Low Q^2
• Two-Photon Exchange Effect Studied with Neural Networks
• New Measurements of the Beam-Normal Single Spin Asymmetry in Elastic Electron Scattering Over a Range of Spin-0 Nuclei
• Beam normal spin asymmetry for the $ep\to e\Delta (1232)$ process
• Lepton-Proton Two-Photon Exchange in Chiral Perturbation Theory
• Two-photon exchange corrections to the pion form factor
• Phenomenological extraction of two-photon exchange amplitudes from elastic electron-proton scattering cross section data
• Nucleon form factors and final state radiative corrections to $e^{+}{e}^{-}\to \bar{p}p\gamma$
• Up- and down-quark contributions to the nucleon electromagnetic form factors at low $Q^2$
• Neural Network Parameterizations of Electromagnetic Nucleon Form Factors
• Target-normal single-spin asymmetry in elastic electron-nucleon scattering
• Two-photon-exchange effects in the unpolarized $\mu p$ scattering within the hadronic model
• Corrections of two-photon interactions in the fine and hyperfine structure of the P-energy levels of muonic hydrogen
• Two-photon exchange corrections to ${\gamma }^{\ast }N\Delta$ form factors for $Q^2\le 4$ (Gev/$c$)${}^2$
• How much two-photon exchange is needed to resolve the proton form factor discrepancy?
• Delta(1232) contribution to real photon radiative corrections for elastic electron-proton scattering
• Beam-normal single-spin asymmetry in elastic scattering of electrons from a spin-0 nucleus
• The ratio of $e^{\pm }p$ scattering cross sections predicted from the global fit of elastic $ep$ data
• Up- and Down-Quark Contributions to the Nucleon Form Factors
• Meson exchange effects in elastic $ep$ scattering at loop level and the electromagnetic form factors of the proton
• Polarized Lepton-Nucleon Elastic Scattering and a Search for a Light Scalar Boson
• Model independent radiative corrections to elastic deuteron-electron scattering
• Determination of two-photon exchange via $e^{+}p/e^{-}p$ Scattering with CLAS12
• Study of Two-Photon Corrections in the $p\bar{p}-->e+e-$ Process: Hard Rescattering Mechanism
• Lepton mass effects for beam-normal single-spin asymmetry in elastic muon-proton scattering
• Parity-Violating Inelastic Electron-Proton Scattering at Low $Q^2$ Above the Resonance Region
• Generalized Sachs Form Factors and the Possibility of Their Measurement in Processes without and with Proton Spin Flip
• A theory vade mecum for PSI experiments
• Target-Normal Single Spin Asymmetries Measured with Positrons
• Elastic Positron-Proton Scattering at Low Q${}^2$
• Dispersive Corrections to the Born Approximation in Elastic Electron-Nucleus Scattering in the Intermediate Energy Regime
• Polarization transfer in ${\vec{e}}^{+}p\to e^{+}\vec{p}$ scattering using the Super BigBite Spectrometer
• Flavour structure of the nucleon electromagnetic form factors and transverse charge densities in the chiral quark-soliton model
• On the cancellation of radiative corrections to the cross section of electron-proton scattering
• Disperon QED
• Resonances contribution to two-photon exchange effects and possible large forward-backward asymmetry in $e^{+}{e}^{-}\to p\bar{p}$
• Two-Boson Exchange Physics: A Brief Review
• Reliability Analysis of the Results of the Known Experiments on Measuring of the Sachs Form Factor Ratio Using the Rosenbluth Technique. Polarization of the Final Proton in the $e\vec{p}\to e\vec{p}$ Elastic Process
• Radiative corrections in nucleon time-like form factors measurements
• Electron Beam Single-Spin Asymmetries in the Resonance Region with Final Hadrons Observed
• Polarization Observables using Positron Beams
• Target normal single-spin asymmetry in inclusive electron-nucleon scattering in the 1/Nc expansion
• Target normal single-spin asymmetry in inclusive electron-nucleon scattering with two-photon exchange: Analysis using $1/N_c$ expansion
• Overview of nucleon structure studies
• Charge and spin asymmetries in elastic lepton-nucleon scattering
• Resonance Contributions to Radiative Corrections in Charged-Current Elastic (Anti)Neutrino-Nucleon Scattering at GeV Energies
• Direct TPE Measurement via $e^{+}p/e^{-}p$ Scattering at low $\epsilon$ in Hall A
• Unpolarized nucleon structure studies utilizing polarized electromagnetic probes
• On the physics behind the form factor ratio ${\mu }_p{G}_E^p(Q^2)/G_M^p(Q^2)$
• Two-photon contributions to the Rosenbluth cross-section in the Skyrme model