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A scheme of simplified smooth hybrid inflation is realized in the framework of supersymmetric SU(5). The smooth model of hybrid inflation provides a natural solution to the monopole problem that appears in the breaking of SU(5) gauge symmetry. The SUGRA corrections with non-minimal K\"ahler potential are shown to play important role in realizing inflation with a red-tilted scalar spectral index ns<1, within Planck's latest bounds. As compared to shifted model of hybrid inflation, relatively large values of the tensor to scalar ratio r≲0.01 are achieved here, with non-minimal couplings −0.01≲κSS≲0.05 and −1≲κSS≲0.4 and the gauge symmetry breaking scale M≃(3.3−16.6)×1016 GeV. [ABSTRACT FROM AUTHOR]

We consider a supersymmetric hybrid inflation scenario in which the U(1) R symmetry is explicitly broken by Planck scale suppressed operators in the superpotential. We provide an example with minimal Kähler potential, with the R-symmetry breaking term relevant during inflation being aS4, where S denotes the well-known gauge singlet inflaton superfield. The inflationary potential takes into account the radiative and supergravity corrections as well as the soft supersymmetry breaking terms. For successful inflation, with the scalar spectral index in the currently preferred range, ns0.97±0.010, |a|=10-7. The tensor-to-scalar ratio r<10-4, while |dns/d ln k|O(10-3) - O(10-4). [ABSTRACT FROM AUTHOR]

We consider a simplified version of supersymmetric smooth hybrid inflation which contains a single ultraviolet cutoff mP = 2.4 × 1018 GeV, instead of the two cutoffs mP and M* ∼ few × 1017 GeV that are normally employed. With global supersymmetry the scalar spectral index ns ≃ 0.97, which is in very good agreement with the WMAP observations. With a nonminimal Kahler potential, the supergravity version of the model is compatible with the current central values of ns and also yields potentially observable gravity waves (tensor to scalar ratio r ≲ 0.02). [ABSTRACT FROM AUTHOR]

We consider supersymmetric shifted hybrid inflation models with a red-tilted scalar spectral index ns in agreement with the WMAP 7-yr central value. If nonminimal supergravity corrections are included, these models can also support a tensor-to-scalar ratio as large as r ≃ 0.02, which may be observable by the Planck Satellite. In contrast to the standard supersymmetric hybrid inflation scenario, topological defects produced via gauge symmetry breaking are inflated away in the shifted version of the theory. [ABSTRACT FROM AUTHOR]

It is shown that a tensor-to-scalar ratio close to r = 0.03, which can be observed by Planck, is realized in supersymmetric hybrid inflation models with TeV-scale soft supersymmetry breaking terms. This extends our previous analysis, which also found r ≲ 0.03 but employed intermediate scale soft terms. Other cosmological observables such as the scalar spectral index are in good agreement with the WMAP data. [ABSTRACT FROM AUTHOR]

We investigate supersymmetric hybrid inflation in a realistic model based on the gauge symmetry SU(4)c×SU(2)L×SU(2)R. The minimal supersymmetric standard model (MSSM) μ term arises, following Dvali, Lazarides, and Shafi, from the coupling of the MSSM electroweak doublets to a gauge singlet superfield, which plays an essential role in inflation. The primordial monopoles are inflated away by arranging that the SU(4)c×SU(2)L×SU(2)R symmetry is broken along the inflationary trajectory. The interplay between the (above) μ coupling, the gravitino mass, and the reheating following inflation is discussed in detail. We explore regions of the parameter space that yield gravitino dark matter and observable gravity waves with the tensor-to-scalar ratio r∼10-4-10-3. [ABSTRACT FROM AUTHOR]

In μ-hybrid inflation a nonzero inflaton vacuum expectation value induced by supersymmetry breaking is proportional to the gravitino mass m3/2, which can be exploited to resolve the minimal supersymmetric standard model μ problem. We show how this scenario can be successfully implemented with m3/2~1-100 TeV and reheat temperature as low as 106 GeV by employing a minimal renormalizable superpotential coupled with a well-defined nonminimal Kähler potential. The tensor-to-scalar ratio r, a canonical measure of primordial gravity waves, in most cases is less than or of the order of 10-6-10-3. [ABSTRACT FROM AUTHOR]