Five--Branes and Supersymmetry Breaking in M--Theory

TL;DR

This work analyzes supersymmetry breaking via gaugino condensation in heterotic M-theory vacua with five-branes and non-standard embeddings. It shows that Hořava's global breaking mechanism persists and that the gaugino-condensation superpotential retains its standard form, while order-$\epsilon$ threshold corrections to gauge kinetic functions and matter Kahler metrics depend on five-brane moduli $Z^n$. The authors derive the 4D ${\cal N}=1$ effective action with explicit $f^{(1)}$, $f^{(2)}$, $Z_{IJ}$, and $W_{\rm gaugino}$ incorporating $Z^n$-dependence, and analyze the universality of soft SUSY-breaking terms, finding universality only in special cases such as $h^{1,1}=1$. They discuss phenomenological implications, including how the pattern of SUSY breaking (via $F^S$, $F^i$, or $F^n$) sets soft-term sizes and the potential role of hidden brane sectors for dilaton stabilization. The work highlights the intricate interplay between brane moduli and low-energy physics in strongly coupled heterotic constructions.

Abstract

Supersymmetry breaking via gaugino condensation is studied in vacua of heterotic M-theory with five-branes. We show that supersymmetry is still broken by a global mechanism and that the non-perturbative superpotential takes the standard form. When expressed in terms of low energy fields, a modification arises due to a threshold correction in the gauge kinetic function that depends on five-brane moduli. We also determine the form of the low energy matter field Kahler potential. These results are used to discuss the soft supersymmetry breaking parameters, in particular the question of universality.