No abstract

The role of string loop corrections on the existence of de Sitter vacua and the moduli stabilization problem is examined in type IIB effective theories. The fundamental building blocks are a minimum of three intersecting D7 brane stacks, three Kähler moduli, and a novel Einstein‐Hilbert term associated with higher derivative terms of the 10‐dimensional effective action. It was shown in previous works that loop corrections appear which induce novel logarithmic volume‐dependent terms in the effective potential. When D‐term contributions are considered, all Kähler moduli are stabilized and de Sitter vacua are achieved. In the present work, a comprehensive study of multiple non‐perturbative terms in the superpotential is undertaken. The combined effects of the logarithmic loop corrections and two non‐perturbative superpotential Kaehler moduli dependent terms have been investigated. It is shown that a variety of fluxes exist for large as well as moderate volume compactifications which define a de Sitter space and stabilize the moduli fields. For large volumes, a generic simple form of the potential is achieved. The so obtained effective potential appears to be promising for cosmological applications.

We investigate the low energy properties of an effective local model with flipped $$SU(5)\times U(1)_{\chi }$$ S U ( 5 ) × U ( 1 ) χ gauge group, constructed within the framework of F-theory. Its origin is traced back to the SO(10) symmetry – associated with a geometric singularity of the compactification manifold – broken by an internal flux which is turned on along the seven-brane in the $$U(1)_{\chi }$$ U ( 1 ) χ direction. Topological properties and the choice of flux parameters determine the massless spectrum of the model to be that of the minimal flipped SU(5) supplemented with an extra right-handed electron-type state and its complex conjugate, $$E^c+{{\bar{E}}}^c$$ E c + E ¯ c , as well as neutral singlet fields. The subsequent symmetry breaking to the $$SU(3)\times SU(2)\times U(1)_Y$$ S U ( 3 ) × S U ( 2 ) × U ( 1 ) Y gauge group occurs with a Higgs pair in $$10+{\overline{10}}$$ 10 + 10 ¯ representations of SU(5). Next we proceed to the phenomenological analysis of the resulting effective model and the salient outcomes are: The $$E^c+{{\bar{E}}}^c$$ E c + E ¯ c pair acquires a mass of few TeV and as such could solve the $$g_{\mu }-2$$ g μ - 2 discrepancy. Neutrino couplings to extra neutral singlets lead to an inverse seesaw mechanism where an extra light state could be a suitable dark matter candidate. The predictions of the model for the $${0\nu }\beta \beta $$ 0 ν β β decay rate could be tested in near future experiments. There are non-unitarity deviations from the lepton mixing matrix $$(U_{PMNS}),$$ ( U PMNS ) , which could in principle explain the new precision measurement of the W-boson mass recently reported by the CDF II collaboration.