6D supergravity without tensor multiplets

TL;DR

This paper classifies six-dimensional N=1 supergravity theories without tensor multiplets, identifying models with novel matter content and potential for new string theory realizations, especially those saturating anomaly bounds.

Contribution

It systematically explores possible gauge groups and matter content, revealing models with unique matter representations and no known string theory counterparts.

Findings

Identified models with novel matter representations.

Found models saturating gravitational anomaly bounds.

Discovered theories with rigid symmetry structures.

Abstract

We systematically investigate the finite set of possible gauge groups and matter content for N = 1 supergravity theories in six dimensions with no tensor multiplets, focusing on nonabelian gauge groups which are a product of SU(N) factors. We identify a number of models which obey all known low-energy consistency conditions, but which have no known string theory realization. Many of these models contain novel matter representations, suggesting possible new string theory constructions. Many of the most exotic matter structures arise in models which precisely saturate the gravitational anomaly bound on the number of hypermultiplets. Such models have a rigid symmetry structure, in the sense that there are no moduli which leave the full gauge group unbroken.