Forms of Relativistic Dynamics, Current Operators and Deep Inelastic Lepton-Nucleon Scattering

TL;DR

This paper examines different forms of relativistic dynamics and their implications for constructing current operators, revealing limitations of the impulse approximation in the front form and supporting the point form's consistency with experimental data in deep inelastic scattering.

Contribution

It clarifies the equivalence of relativistic dynamics forms and analyzes the impulse approximation's validity, especially highlighting the point form's suitability for deep inelastic scattering.

Findings

Impulse approximation is only reasonable in the point form.

Parton model sum rules exceed experimental values due to impulse approximation limitations.

Point form provides a natural qualitative explanation for experimental results.

Abstract

The three well-known forms of relativistic dynamics are unitarily equivalent and the problem of constructing the current operators can be solved in any form. However the notion of the impulse approximation is reasonable only in the point form. In particular, the parton model which is the consequence of the impulse approximation in the front form is incompatible with Lorentz invariance, P invariance and T invariance. The results for deep inelastic scattering based on the impulse approximation in the point form give natural qualitative explanation of the fact that the values given by the parton model sum rules exceed the corresponding experimental quantities.