Fixed-axis polarization states: covariance and comparisons

TL;DR

This paper proves the Lorentz covariance of fixed-axis polarization states and connects them to conventional states, enabling the construction of pure S-wave nucleon models.

Contribution

It demonstrates the Lorentz covariance of fixed-axis polarization states and establishes their relation to traditional polarization states, facilitating S-wave nucleon modeling.

Findings

Fixed-axis polarization states are Lorentz covariant.

Explicit connection to conventional polarization states is established.

Pure S-wave nucleon models can be constructed using these states.

Abstract

Addressing the recent criticisms of Kvinikhidze and Miller, we prove that the spectator wave functions and currents based on ``fixed-axis'' polarization states (previously introduced by us) are Lorentz covariant, and find an explicit connection between them and conventional direction-dependent polarization states. The discussion shows explicitly how it is possible to construct pure $S$-wave models of the nucleon.