Abstract
We propose a new mechanism of (geometric) moduli stabilisation in type IIB/F-theory four-dimensional compactifications on Calabi–Yau manifolds, in the presence of 7-branes, that does not rely on non-perturbative effects. Complex structure moduli and the axion-dilaton system are stabilised in the standard way, without breaking supersymmetry, using 3-form internal fluxes. Kähler class moduli stabilisation utilises perturbative string loop corrections, together with internal magnetic fields along the D7-branes world-volume leading to Fayet-Iliopoulos D-terms in the effective supergravity action. The main ingredient that makes the stabilisation possible at a de Sitter vacuum is the logarithmic dependence of the string loop corrections in the large two-dimensional transverse volume limit of the 7-branes.
Highlights
The String Theory landscape comprises an enormous number of vacua, not all of them are consistent with the cosmological data and the relevant for particle physics effective N = 1 supergravity theories
We propose a new mechanism of moduli stabilisation in type IIB/F-theory four-dimensional compactifications on Calabi–Yau manifolds, in the presence of 7-branes, that does not rely on non-perturbative effects
The key point towards a convincing solution is to implement a realistic dynamical mechanism which generates a scalar potential and provides masses to the various massless scalar fields emerging in string compactifications
Summary
DS vacua can only be obtained by ‘uplifting’ the vacuum energy in the presence of anti-D3 branes (D3-branes for short), which break though supersymmetry explicitly (KKLT scenario [5]) This situation can, in principle, be remedied if instead of D3branes, D-term contributions are taken into account in the effective action [18,19,20,21,22,23,24], emerging from internal magnetic fluxes along the D7-branes world volume. The logarithmic dependence is quite general in the presence of two large transverse dimensions, as shown for example in [28] Combining these effects with D-term contributions, we show that all Kähler moduli can be stabilised in a dS vacuum of broken supersymmetry.
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