No scale Hybrid inflation with R-symmetry breaking

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. We explore all regions in the parameter space when discussing the observables. The effective inflation potential is asymptotically flat in a region of the parameter space in both cases. We discuss the constraints on the parameter space from inflation. We point out a connection between inflation, R-symmetry breaking and GUT scales. The moduli backreaction and SUSY breaing 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 $Z_2$ associated with flipped GUT models to avoid phenomenologically dangerous operators and allow for decay channels for the inflaton to right-handed neutrinos (sneutrinos).