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F-Term Hybrid Inflation, the η-problem and Extra Dimensions

John McDonald
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Abstract

F-term hybrid inflation models in the context of supergravity generically have corrections to the inflaton mass squared of the order of H^{2} (the η-problem). In addition they have a problem with large deviations of the spectrum of density perturbations from scale-invariance due to non-renormalizable corrections to the superpotential. Here we show that an increase of the expansion rate at large energy densities relative to that in conventional d=4 cosmology, as suggested by the single brane Randall-Sundrum scenario with an uncompactified extra dimension, can naturally solve the ηproblem. This requires that the d=5 Planck mass satisfies M_{5} < 10^{16} GeV. In addition, the scale-invariance of the density perturbation spectrum can be generally protected from Planck-suppressed superpotential corrections if M_{5} < 10^{10} \GeV

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John McDonald. 2003-09-11. F-Term Hybrid Inflation, the η-problem and Extra Dimensions. https://doi.org/10.1088/1126-6708%2F2002%2F12%2F029

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