# Contribution of Two-Boson-Exchange with $Δ1232$ Excitation to Parity-Violating Elastic Electron-Proton Scattering - Nuclear Theory

Contribution of Two-Boson-Exchange with $Δ1232$ Excitation to Parity-Violating Elastic Electron-Proton Scattering - Nuclear Theory - Download this document for free, or read online. Document in PDF available to download.

Abstract: We study the leading electroweak corrections in the precision measurement ofthe strange form factors. Specifically, we calculate the two-boson-exchangeTBE, two-photon-exchange TPE plus $\gamma Z$-exchange $\gamma Z$E,corrections with $\Delta1232$ excitation to the parity-violating asymmetry ofthe elastic electron-proton scattering. The interplay between nucleon and$\Delta$ contributions is found to depend strongly on the kinematics, as$\delta \Delta$ begins as negligible at backward angles but becomes very largeand negative and dominant at forward angles, while $\delta N$ always stayspositive and decreases monotonically with increasing $\epsilon$. The total TBEcorrections to the extracted values of $G^{s} {E}+\beta G^{s} {M}$ in recentexperiments of HAPPEX and G0 are, depending on kinematics, found to be largeand range between 13% to -75% but small in the case of A4 experiments.

Author: Keitaro Nagata, Hai Qing Zhou, Chung Wen Kao, Shin Nan Yang

Source: https://arxiv.org/