Radiative corrections to the parity-violating spin asymmetry

TL;DR

This paper evaluates the parity-violating spin asymmetry in elastic electron scattering from spin-zero nuclei, including QED and dispersion corrections, across a range of energies and angles, with implications for nuclear structure and experiments.

Contribution

It provides a non-perturbative evaluation of Apv with dispersion corrections for various nuclei and energies, highlighting the significance of nuclear excitations at different regimes.

Findings

Dispersion corrections are negligible at GeV energies and small angles.

Low-lying nuclear excitations significantly affect Apv at lower energies and backward angles.

Results are provided for $^{12}$C and $^{208}$Pb targets across 5-500 MeV energies.

Abstract

The parity-violating spin asymmetry Apv for elastic electron scattering from spin-zero nuclei, together with its QED corrections, is evaluated non-perturbatively within the phase-shift analysis. Dispersion corrections, taking into account low-lying transient nuclear excitations, are estimated with the help of the lowest-order $\gamma Z$ box diagrams. Collision energies between 5 $-$ 500 MeV are considered, and results are provided for the $^{12}$C and $^{208}$Pb target nuclei. In addition, we have evaluated Apv at GeV energies and small scattering angles -- relevant for the Pb Radius Experiment (PREx) -- revealing that the low-lying nuclear excited states give no measurable dispersive contribution. However, they are important at lower energies and backward angles.