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Two-photon-exchange correction to parity-violating elastic electron-proton scattering.
Andrei V Afanasev1, Carl E Carlson
1Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA.
Physical Review Letters
|August 11, 2005
Summary
We calculated a two-photon-exchange quantum electrodynamics (QED) correction for electron-proton scattering. This higher-order QED effect can significantly impact precision measurements of proton form factors.
Area of Science:
- Nuclear Physics
- Quantum Electrodynamics (QED)
- Particle Physics
Background:
- Higher-order QED effects are crucial for precise nucleon elastic form factor measurements in electron scattering.
- Understanding these effects is essential for interpreting experimental data accurately.
Purpose of the Study:
- To introduce and calculate a two-photon-exchange QED correction for the parity-violating polarization asymmetry in elastic electron-proton scattering.
- To assess the significance of this correction in specific kinematic regimes.
Main Methods:
- Utilized the parton model and the formalism of generalized parton distributions.
- Performed calculations for the two-photon-exchange QED correction.
Main Results:
- The calculated two-photon-exchange QED correction can reach several percent in certain kinematics.
- This correction's magnitude is comparable to experimental measurements of strange-quark effects in the proton's neutral weak current.
Conclusions:
- The two-photon-exchange QED correction is a significant factor in precision measurements of elastic electron-proton scattering.
- This finding necessitates its inclusion for accurate analysis of proton structure and weak interactions.