Low Energy Supersymmetry From the Landscape

TL;DR

The paper investigates whether the string theory landscape predicts low-energy supersymmetry. Using the KKLT framework as a concrete realization of the flux discretuum, it analyzes how moduli are stabilized and how SUSY breaking scales distribute across vacua, highlighting a roughly $\log$-flat distribution for dynamical breaking and the potential role of nonperturbative dynamics. It argues that discrete or accidental symmetries can create many $W=0$ vacua, biasing toward very low SUSY-breaking scales under a Pragmatic Anthropic Principle that fixes $\Lambda$, the weak scale, and related observables. While Higgs-mass constraints and a vanishing leading $\mu$ term can temper the favors toward ultra-low scales, warping and other pathways may still bias toward supersymmetric solutions. The authors conclude that the landscape can be predictive and possibly falsifiable, contingent on the prevalence of discrete symmetries and nonperturbative dynamics, thus sharpening notions of naturalness rather than abolishing them.

Abstract

There has been some debate as to whether the landscape does or does not predict low energy supersymmetry. We argue that under rather mild assumptions, the landscape seems to favor such breaking, quite possibly at a very low scale. Some of the issues which must be addressed in order to settle these questions are the relative frequency with which tree level and non-perturbative effects generate expectation values for auxillary fields and the superpotential, as well as the likelihood of both $R$- and non-$R$ discrete or accidental symmetries. Alternate scenarios with warped compactifications or large extra dimensions are also discussed.