Fine-tuning problems in type IIA string theory
摘要
We demonstrate a unified resolution to the strong CP, hierarchy, and cosmological constant problems in type IIA flux compactifications, via 4-form fluxes and KL stabilization. We show that the strong CP problem can be effectively “solved” in type IIA orientifold constructions, particularly in the type IIA T6/(ℤ2 × ℤ2) model. Building on this, we explore whether the remaining two fine-tuning problems can also be resolved within the same setup. To obtain a small cosmological constant, we adopt the KL scenario and find that, in order to avoid conflicts with the swampland distance conjecture and to eliminate the need for fine-tuning, the perturbative superpotential ∆W must take the form f0U 3. Additionally, we compute the gravitino mass. This allows for a resolution of the hierarchy problem without introducing fine-tuning if gravitino mass lies below 100 TeV. Taken together, these results suggest that the type IIA T6/(ℤ2 × ℤ2) orientifold model provides a promising framework in which all three fine-tuning problems may be addressed simultaneously.