Abstract
In this paper we provide a no-scale supergravity scenario of hybrid inflation with R-symmetry being broken maximally. We investigate the inflation dynamics in details in both cases of pure F-term hybrid inflation and when adding constant Fayet-Iliopoulos D-terms. The effective inflation potential is asymptotically flat in a region of the parameter space in both cases. We explore all regions in the parameter space when discussing the constraints from the observables. We point out a connection between inflation, R-symmetry breaking and GUT scales. The moduli backreaction and SUSY breaking effects are investigated in a specific stabilization mechanism. We emphasis that a successful reheating is not affected by R-symmetry breaking, but it has interesting consequences. We study the reheating in flipped GUT model. We argue in favor of Z2 symmetry associated with flipped GUT models to avoid phenomenologically dangerous operators and allow for decay channels for the inflaton to right-handed neutrinos (sneutrinos).
Highlights
The η-problem: it appears due to the supergravity contributions to the inflaton mass which spoils the slow-roll conditions, 1, η 1
In this paper we provide a no-scale supergravity scenario of hybrid inflation with R-symmetry being broken maximally
Supersymmetry breaking in an approximate flat space: after the end of inflation, the inflaton goes to its true minimum and supersymmetry should be broken in an approximate flat space with infinitesimal vacuum energy density V 10−120MP4 according to recent observations that supports a very tiny cosmological constant
Summary
The fields α, β, y are fixed at the origin during the inflation, since the scalar potential is minimized for α = β = y = 0 and their inflaton field dependent masses are larger than the Hubble scale during inflation as follows m2y H2. As the inflaton rolls down, its value decreases to smaller values until it reaches a critical value xc at which the field dependent mass m2α changes to negative and α = 0 becomes a local maximum as ind√icated in figure 1. This triggers the waterfall phase and α goes to its true minimum α = 2M. The time has been rescaled by the Hubble constant H
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