The Vector Analyzing Power in Elastic Electron-Proton Scattering

Abstract

We compute the vector analyzing power (VAP) for the elastic scattering of transversely polarized electrons from protons at low energies using an effective theory of electrons, protons, and photons. We study all contributions through second order in $E/M$, where $E$ and $M$ are the electron energy and nucleon mass, respectively. The leading order VAP arises from the imaginary part of the interference of one- and two-photon exchange amplitudes. Sub-leading contributions are generated by the nucleon magnetic moment and charge radius as well as recoil corrections to the leading-order amplitude. Working to $\mathcal{O}(E/M{)}^2$, we obtain a prediction for $A_n$ that is free of unknown parameters and that agrees with the recent measurement of the VAP in backward angle $ep$ scattering.

24 pages, 11 figures. Typos fixed

References in corpus (14)

• Two-photon exchange and elastic electron-proton scattering
• Partonic calculation of the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer
• Virtual Compton Scattering off the nucleon
• Measurement of the vector analyzing power in elastic electron-proton scattering as a probe of double photon exchange amplitudes
• Resonance estimates for single spin asymmetries in elastic electron-nucleon scattering
• Collinear Photon Exchange in the Beam Normal Polarization Asymmetry of Elastic Electron-Proton Scattering
• New Limit on the D Coefficient in Polarized Neutron Decay
• Constraints on T-Odd, P-Even Interactions from Electric Dipole Moments
• Large Logarithms in the Beam Normal Spin Asymmetry of Elastic Electron--Proton Scattering
• Recoil Order Chiral Corrections to Baryon Octet Axial Currents
• Effective Lagrangians and Parity-Conserving Time-Reversal Violation at Low Energies
• Electric Dipole Moments and the Mass Scale of New T-Violating, P-Conserving Interactions
• Nucleon Compton Scattering with Two Space--Like Photons
• The Nucleon's Mirror Image: Revealing the Strange and Unexpected

Cited by in corpus (13)

• Two-Photon Physics in Hadronic Processes
• 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
• Analyzing power in elastic scattering of the electrons off a spin-0 target
• Dispersive contributions to $e^{+}p/e^{-}p$ cross section ratio in forward regime
• The Vector Analyzing Power in Elastic Electron-Nucleus Scattering
• Transverse single spin asymmetries in inclusive deep-inelastic scattering
• New Measurements of the Beam-Normal Single Spin Asymmetry in Elastic Electron Scattering Over a Range of Spin-0 Nuclei
• Beam normal spin asymmetry in the quasi-RCS approximation
• Doubly virtual Compton scattering and the beam normal spin asymmetry
• Beam-Normal Single Spin Asymmetry in Elastic Electron Scattering off ${}^{28}$Si and ${}^{90}$Zr
• Beam normal spin asymmetry of elastic $eN$ scattering in the leading logarithm approximation
• Study of Two-Photon Exchange via the Beam Transverse Single Spin Asymmetry in Electron-Proton Elastic Scattering at Forward Angles over a Wide Energy Range
• Measurement of the Beam-Normal Single-Spin Asymmetry for Elastic Electron Scattering from ${}^{12}$C and ${}^{27}$Al