The $γZ$-box correction and its impact on parity-violating deep-inelastic scattering

Abstract

The $γZ$-box correction is an important electroweak contribution to precision parity-violation measurements, but its conventional low-energy treatment relies on an ambiguous effective quark-mass prescription. We revisit this correction using a finite-mass calculation that provides a well-defined perturbative contribution without introducing such an auxiliary scale. Applying the result to the Jefferson Lab PVDIS measurement shifts the extracted electron-quark couplings at the $10^{-3}$ level. We discuss the implications of this shift for precision electroweak tests and the need for a consistent separation of perturbative and non-perturbative hadronic contributions.