Charge Distributions of Moving Nucleons

TL;DR

This paper introduces relativistic charge distributions for moving nucleons, bridging the gap between Breit frame and infinite-momentum frame views, and clarifies their interpretation and discrepancies.

Contribution

It presents a new framework for relativistic charge distributions of moving targets, unifying different frame interpretations and explaining observed discrepancies.

Findings

Breit frame distributions can be viewed as internal charge densities without relativistic correction.

Discrepancies between frames are due to kinematical effects related to spin.

The introduced distributions interpolate between known frame-specific distributions.

Abstract

Relativistic charge distributions of targets with arbitrary average momentum are introduced. They provide an interpolation between the usual Breit frame and infinite-momentum frame distributions. We find that Breit frame distributions can be interpreted from a phase-space perspective as internal charge quasi-densities in the rest frame of a localized target, without any relativistic correction. We show also that the apparent discrepancies between Breit frame and infinite-momentum frame distributions simply result from kinematical artifacts associated with spin.