Absence of the μ-problem in grand unification

Using properties of Goldstino, we show that in generic grand unified theories with gravity-mediated supersymmetry breaking the At-problem is nonexistent. What happens is that supersymmetry breaking universally induces the shifts of the heavy fields that generate At and BAt terms. In the leading order, these are given by the mass of gravitino and are insensitive to the scale of grand unification. The mechanism works regardless whether doublet-triplet splitting is achieved via fine-tuning or not. Moreover, we illustrate this general phenomenon on explicit examples of theories that achieve doublet-triplet splitting dynamically. These include the theories with Higgs doublet as a pseudo-Goldstone boson, as well as the approach based on spontaneous decoupling of the light color triplet from quarks and leptons.

Automated summary

By utilizing Goldstino properties, it has been shown that in generic grand unified theories, the At problem does not exist, and the shifts of heavy fields generating At and BAt terms are induced universally by supersymmetry breaking, regardless of the scale of grand unification. This mechanism works irrespective of whether doublet-triplet splitting is achieved through fine-tuning or not.