Simultaneous Extraction of the Weak Radius and the Weak Mixing Angle from Parity-Violating Electron Scattering on $^{12}\mathrm{C}$

TL;DR

This paper demonstrates that precise measurements of parity-violating electron scattering on carbon-12 can accurately determine its weak charge and radius, with nuclear structure uncertainties being manageable.

Contribution

It introduces a method to extract the weak radius and weak charge of carbon-12 simultaneously using measurements at different angles, accounting for nuclear model uncertainties.

Findings

0.3% precision in asymmetry measurement is sufficient for weak charge determination.

Combining forward and backward angle measurements allows extraction of the weak radius.

Achievable 0.34% precision on the weak radius with 3% asymmetry measurement at backward angles.

Abstract

We study the impact of nuclear structure uncertainties on a measurement of the weak charge of $^{12}\mathrm{C}$ at the future MESA facility in Mainz. Information from a large variety of nuclear models, accurately calibrated to the ground-state properties of selected nuclei, suggest that a $0.3$% precision measurement of the parity-violating asymmetry at forward angles will not be compromised by nuclear structure effects, thereby allowing a world-leading determination of the weak charge of $^{12}\mathrm{C}$. Furthermore, we show that a combination of measurements of the parity-violating asymmetry at forward and backward angles for the same electron beam energy can be used to extract information on the nuclear weak charge distribution. We conclude that a $0.34$% precision on the weak radius of $^{12}\mathrm{C}$ may be achieved by performing a $3$% precision measurement of the parity-violating asymmetry at backward angles.