Unification of Spacetime Symmetries of Massive and Massless Particles

TL;DR

This paper explores the unification of spacetime symmetries for massive and massless particles, revealing they are different manifestations of a single covariant symmetry group, with implications for particle models.

Contribution

It demonstrates that the internal symmetries of massive and massless particles are unified under a single covariant group, linking different little groups and particle models.

Findings

The $O(3)$ and $E(2)$ little groups are unified under a covariant framework.

Quark and parton models are shown as different manifestations of the same symmetry.

The unification provides a deeper understanding of particle internal symmetries.

Abstract

The internal space-time symmetries of relativistic particles are dictated by Wigner's little groups. The $O(3)$-like little group for a massive particle at rest and the $E(2)$-like little group of a massless particle are two different manifestations of the same covariant little group. Likewise, the quark model and parton pictures are two different manifestations of the one covariant entity.