Dilaton stabilization in KKLT revisited

We study the condition for the dilaton stabilization in Type IIB flux compactifications consistent with the KKLT scenario. Since the Gukov-Vafa-Witten superpotential depends linearly on the dilaton, the dilaton mass squared is given by a sum of the gravitino mass squared and additional terms determined by the complex structure moduli stabilization. If the dilaton mass is not much enhanced from the gravitino mass, the mass mixing with the Kahler modulus in the presence of the non-perturbative effect generates the saddle point at the supersymmetric field values, hence the potential becomes unstable. When the complex structure moduli other than the conifold modulus are neglected, the saddle point problem arises over the controllable parameter space. We also point out that the dilaton stabilization condition is equivalent to the condition on the NS 3-form fluxes, vertical bar H-(1,H-2)vertical bar >vertical bar H-(0,H-3)vertical bar. (C) 2021 The Author(s). Published by Elsevier B.V.

Automated summary

In Type IIB flux compactifications consistent with the KKLT scenario, the condition for dilaton stabilization was studied. The dilaton mass squared, depending linearly on the dilaton, is determined by a sum of the gravitino mass squared and additional terms related to the complex structure moduli stabilization. It was found that when the dilaton mass is not significantly larger than the gravitino mass, the potential becomes unstable due to mass mixing with the Kahler modulus and saddle point generation at supersymmetric field values.