BPS States in Superstrings with Spontaneously Broken SUSY

TL;DR

This paper demonstrates a mechanism for spontaneous supersymmetry breaking in string theory, linking BPS spectra across different supersymmetry levels and proposing a method to determine the exact non-perturbative prepotential of N=2 supergravity.

Contribution

It introduces a supersymmetry-breaking mechanism with moduli-dependent gravitino masses and relates the BPS spectra of theories with different supersymmetries, offering a new approach to compute non-perturbative prepotentials.

Findings

BPS spectrum in lower SUSY theories matches heterotic N=4 spectrum.

Mass splitting depends on moduli and R-charges.

Perturbative N=2 prepotential determined by N=4 BPS states.

Abstract

We show the existence of a supersymmetry-breaking mechanism in string theory, where N=4 supersymmetry is broken spontaneously to N=2 and N=1 with moduli-dependent gravitino masses. The BPS spectrum of the theory with lower supersymmetry is in one-to-one correspondence with the spectrum of the heterotic N=4 string. The mass splitting of the N=4 spectrum depends on the moduli as well as the three R-symmetry charges. In the case of N=4 \to N=2, the perturbative N=2 prepotential is determined by the perturbative N=4 BPS states. This observation led us to suggest a method that determines the exact non-perturbative prepotential of the effective N=2 supergravity using the shifted spectrum of the non-perturbative BPS states of the underlying N=4 theory.