Low-Energy 𝛾Z-box Effects on the Proton Weak Charge

by Balma Duch

Wednesday Mar 25, 2026, 1:00 PM → 2:00 PM Europe/Madrid

IFAE Seminar Room (In-person)

The determination of the proton’s weak charge via parity-violating electron scattering is a key frontier for testing the Standard Model and searching for new physics. However, interpreting these experiments is currently limited by theoretical uncertainties in electroweak radiative corrections, in particular the 𝛾Z-box diagrams.

 

In this talk, I will present a detailed study of the 𝛾Z-box correction in low-energy electron-quark scattering. We perform a one-loop calculation keeping both the electron and quark masses non-zero, and extract well-defined low-energy effective couplings relevant for parity-violating interactions. I will explain how our results resolve long-standing ambiguities in the literature, clarify the role of the Sommerfeld enhancement, and provide a framework to separate perturbative effects from non-perturbative proton structure. Finally, I will discuss the impact of these corrections on the determination of the proton’s weak charge and their significance for precision tests of the Standard Model.