Higher Spins and Open Strings: Quartic Interactions

TL;DR

This paper investigates quartic interactions of massless higher spin fields within superstring theory, revealing their non-local nature and explicitly computing specific four-point amplitudes involving spins 1, 3, and 5.

Contribution

It introduces a method to analyze higher spin interactions using vertex operators and computes explicit four-point amplitudes, advancing understanding of their gauge-invariant structures.

Findings

Explicit four-point amplitude for 1-1-3-3 interaction.

Identification of non-locality due to ghost structure.

Comments on general 1-1-s-s interactions, including 1-1-5-5.

Abstract

We analyze quartic gauge-invariant interactions of massless higher spin fields by using vertex operators constructed in our previous works and computing their four-point amplitudes in superstring theory. The kinematic part of the quartic interactions of the higher spins is determined by the matter structure of their vertex operators;the non-locality of the interactions is the consequence of specific ghost structure of these operators. We compute explicitly the four-point amplitude describing the complete gauge-invariant $1-1-3-3$ quartic interaction (two massless spin 3 particles interacting with two photons) and comment on more general $1-1-s-s$ cases, particularly pointing out the structure of $1-1-5-5$ coupling.