Revisiting Gauge Ambiguities for DUNE Precision

TL;DR

This paper examines gauge ambiguities in lepton-nucleus scattering, compares existing methods, and proposes a new off-shell current approach to improve precision for future neutrino experiments.

Contribution

It introduces a novel off-shell current method to address gauge ambiguities, offering a systematically improvable solution.

Findings

Differences between prescriptions are significant for next-generation experiments.

Existing methods have gauge invariance issues.

The proposed approach improves theoretical consistency.

Abstract

The de Forest prescription for handling off-shell initial states in the impulse approximation for lepton-nucleus scattering breaks gauge invariance. We discuss existing methods to address this problem and handle the form factor scale ambiguity. We demonstrate that the irreducible differences between the prescriptions are significant compared to the precision expected of next-generation accelerator neutrino experiments. A novel approach directly using the off-shell currents is proposed as a systematically improvable alternative.