The most promising MSSM candidates of the heterotic string reveal some distinctive properties. These include gauge-top unification, a specific solution to the μ-problem and mirage pattern for the gaugino masses. The location of the top- and the Higgs-multiplets in extra dimensions differs significantly from that of the other quarks and leptons leading to a characteristic signature of suppressed soft breaking terms, reminiscent of a scheme known as natural supersymmetry. © 2012 Elsevier B.V.

We revisit the implications of naturalness and gauge unification in the minimal supersymmetric standard model. We find that precision unification of the couplings in connection with a small μ parameter requires a highly compressed gaugino pattern as it is realized in mirage mediation. Due to the small mass difference between the gluino and lightest supersymmetric particle (LSP), collider limits on the gluino mass are drastically relaxed. Without further assumptions, the relic density of the LSP is very close to the observed dark matter density due to coannihilation effects. © 2013 American Physical Society.