F-Term Hybrid Inflation Followed by a Peccei-Quinn Phase Transition

We consider a cosmological set-up, based on renormalizable superpotential terms, in which a superheavy scale F-term hybrid inflation is followed by a Peccei-Quinn phase transition, resolving the strong CP and mu problems of the minimal supersymmetric standard model. We show that the field which triggers the Peccei-Quinn phase transition can remain after inflation well above the Peccei-Quinn scale thanks to (i) its participation in the supergravity and logarithmic corrections during the inflationary stage and (ii) the high reheat temperature after the same period. As a consequence, its presence influences drastically the inflationary dynamics and the universe suffers a second period of reheating after the Peccei-Quinn phase transition. Confronting our inflationary predictions with the current observational data, we find that, for about the central value of the spectral index, the grand unification scale can be identified with its supersymmetric value for the relevant coupling constant \kappa=0.002 and, more or less, natural values, +/-(0.01-0.1), for the remaining parameters. On the other hand, the final reheat temeperature after the Peccei-Quinn phase transition turns out to be low enough so as the gravitino problem is avoided.Comment: 15 pages including 8 figures, version published in Phys. Rev.

Shift Symmetry and Higgs Inflation in Supergravity with Observable Gravitational Waves

We demonstrate how to realize within supergravity a novel chaotic-type inflationary scenario driven by the radial parts of a conjugate pair of Higgs superfields causing the spontaneous breaking of a grand unified gauge symmetry at a scale assuming the value of the supersymmetric grand unification scale. The superpotential is uniquely determined at the renormalizable level by the gauge symmetry and a continuous R symmetry. We select two types of Kahler potentials, which respect these symmetries as well as an approximate shift symmetry. In particular, they include in a logarithm a dominant shift-symmetric term proportional to a parameter c- together with a small term violating this symmetry and characterized by a parameter c+. In both cases, imposing a lower bound on c-, inflation can be attained with subplanckian values of the original inflaton, while the corresponding effective theory respects perturbative unitarity for r+-=c+/c-<1. These inflationary models do not lead to overproduction of cosmic defects, are largely independent of the one-loop radiative corrections and accommodate, for natural values of r+-, observable gravitational waves consistently with all the current observational data. The inflaton mass is mostly confined in the range (3.7-8.1)x10^10 GeV.Comment: Final version with some typos correcte

Yukawa Quasi-Unification and Inflation

We review the construction of a concrete supersymmetric grand unified model, which naturally leads to a moderate violation of "asymptotic" Yukawa unification and, thus, can allow an acceptable b-quark mass within the constrained minimal supersymmetric standard model with mu>0. The model possesses a wide and natural range of parameters which is consistent with the data on the cold dark matter abundance in the universe, b-->s gamma, the muon anomalous magnetic moment and the Higgs boson masses. Also, it automatically leads to a new version of shifted hybrid inflation, which avoids overproduction of monopoles at the end of inflation by using only renormalizable terms.Comment: Talk presented by G. Lazarides at the BW2003 Workshop, Vrnjacka Banja, Serbia, 29 August-2 September 2003 (to appear in the proceedings), 15 pages including 3 figures, uses ws-procs9x6.cls and rotating_pr.st

Inflation, Leptogenesis, and Yukawa Quasi-Unification within a Supersymmetric Left-Right Model

A simple extension of the minimal left-right symmetric supersymmetric grand unified theory model is constructed by adding two pairs of superfields. This naturally violates the partial Yukawa unification predicted by the minimal model. After including supergravity corrections, we find that this extended model naturally supports hilltop F-term hybrid inflation along its trivial inflationary path with only a very mild tuning of the initial conditions. With a convenient choice of signs of the terms in the Kahler potential, we can reconcile the inflationary scale with the supersymmetric grand unified theory scale. All the current data on the inflationary observables are readily reproduced. Inflation is followed by non-thermal leptogenesis via the decay of the right-handed neutrinos emerging from the decay of the inflaton and any possible washout of the lepton asymmetry is avoided thanks to the violation of partial Yukawa unification. The extra superfields also assist us in reducing the reheat temperature so as to satisfy the gravitino constraint. The observed baryon asymmetry of the universe is naturally reproduced consistently with the neutrino oscillation parameters.Comment: 20 pages including 4 figure

Probing the Supersymmetry-Mass Scale With F-term Hybrid Inflation

We consider F-term hybrid inflation and supersymmetry breaking in the context of a model which largely respects a global U(1) R symmetry. The Kaehler potential parameterizes the Kaehler manifold with an enhanced U(1)x(SU(1,1)/U(1)) symmetry, where the scalar curvature of the second factor is determined by the achievement of a supersymmetry-breaking de Sitter vacuum without ugly tuning. The magnitude of the emergent soft tadpole term for the inflaton can be adjusted in the range (1.2-460) TeV -- increasing with the dimensionality of the representation of the waterfall fields -- so that the inflationary observables are in agreement with the observational requirements. The mass scale of the supersymmetric partners turns out to lie in the region (0.09-253) PeV which is compatible with high-scale supersymmetry and the results of LHC on the Higgs boson mass. The mu parameter can be generated by conveniently applying the Giudice-Masiero mechanism and assures the out-of-equilibrium decay of the R saxion at a low reheat temperature Trh<~163 GeV