Exactly stable non-BPS spinors in heterotic string theory on tori

TL;DR

This paper constructs and proves the stability of a non-supersymmetric heterotic string state on T^4, providing a detailed classification of BPS and non-BPS states and their dual interpretations.

Contribution

It introduces a specific stable non-BPS state in heterotic string theory on T^4 and analyzes its stability across moduli space, expanding understanding of non-supersymmetric string states.

Findings

Constructed a robust non-BPS stable state.

Provided a complete classification of BPS atoms and molecules.

Interpreted results via string dualities and D-brane configurations.

Abstract

Considering SO(32) heterotic string theory compactified on a torus of dimension 4 and less, stability of non-supersymmetric states is studied. A non-supersymmetric state with robust stability is constructed, and its exact stability is proven in a large region of moduli space against all the possible decay mechanisms allowed by charge conservation. Using various T-duality transform matrices, we translate various selection rules about conserved charges into simpler problems resembling partition and parity of integers. For heterotic string on T^4, we give a complete list of BPS atoms with elementary excitations, and we study BPS and non-BPS molecules with various binding energies. Using string-string duality, the results are interpreted in terms of Dirichlet-branes in type IIA string theory compactified on an orbifold limit of a K3 surface.