Continuous spin particles from a string theory

TL;DR

This paper demonstrates how continuous spin representations of the Poincaré group can be derived from a conformally invariant string theory, with a quantized, ghost-free spectrum confirming the theoretical viability of such particles.

Contribution

It introduces a novel string theory model that yields continuous spin representations, extending the understanding of massless particles in quantum field theory.

Findings

Vacuum state carries a continuous spin representation

Spectrum is ghost-free after quantization

String model generalizes point particle action to conformal invariance

Abstract

It has been shown that the massless irreducible representations of the Poincar\'e group with continuous spin can be obtained from a classical point particle action which admits a generalization to a conformally invariant string action. The continuous spin string action is quantized in the BRST formalism. We show that the vacuum carries a continuous spin representation of the Poincar\'e group and that the spectrum is ghost-free.