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We consider the decay of the inflaton in Starobinsky-like models arising from either an R + R 2 theory of gravity or N = 1 no-scale supergravity models. If Standard Model matter is simply introduced to the R + R 2 theory, the inflaton (which appears when the theory is conformally transformed into the Einstein frame) couples to matter predominantly in Standard Model Higgs kinetic terms. This will typically lead to a reheating temperature of ∼3 × 10 9 GeV. However, if the Standard Model Higgs is conformally coupled to curvature, the decay rate may be suppressed and vanishes for conformal coupling ξ = 1 / 6 . Nevertheless, the inflaton decays through the conformal anomaly, leading to a reheating temperature of the order of 10 8 GeV. The Starobinsky potential may also arise in no-scale supergravity. In this case, the inflaton decays if there is a direct coupling of the inflaton to matter in the superpotential or to gauge fields through the gauge kinetic function. We also discuss the relation between the theories and demonstrate the correspondence between the no-scale models and the conformally coupled R + R 2 theory (with ξ = 1 / 6 ). [ABSTRACT FROM AUTHOR]

After reviewing the motivations for cosmological inflation formulated in the formalism of supersymmetry, we argue that the appropriate framework is that of no-scale supergravity. We then show how to construct within this framework inflationary models whose predictions for the tilt in the spectrum of scalar perturbations, n s , and the ratio, r , of tensor and scalar perturbations coincide with those of the R + R 2 model of inflation proposed by Starobinsky. A more detailed study of no-scale supergravity reveals a structure that is closely related to that of R 2 modifications of the minimal Einstein–Hilbert action for general relativity, opening avenues for constructing no-scale de Sitter and anti-de Sitter models by combining pairs of Minkowski models, as well as generalizations of the original no-scale Starobinsky models of inflation. We then discuss the phenomenology of no-scale models of inflation, including inflaton decay and reheating, and then the construction of explicit scenarios based on SU(5), SO(10) and string-motivated flipped SU(5)×U(1) GUT models. The latter provides a possible model of almost everything below the Planck scale, including neutrino masses and oscillations, the cosmological baryon asymmetry and cold dark matter, as well as n s and r. [ABSTRACT FROM AUTHOR]

We describe the resulting phenomenology of string theory/supergravity models with strong moduli stabilization. The KL model with F-term uplifting, is one such example. Models of this type predict universal scalar masses equal to the gravitino mass. In contrast, A-terms receive highly suppressed gravity mediated contributions. Under certain conditions, the same conclusion is valid for gaugino masses, which like A-terms, are then determined by anomalies. In such models, we are forced to relatively large gravitino masses (30-1000 TeV). We compute the low-energy spectrum as a function of m. We see that the Higgs masses naturally takes values between 125-130 GeV. The lower limit is obtained from the requirement of chargino masses greater than 104 GeV, while the upper limit is determined by the relic density of dark matter (wino-like). [ABSTRACT FROM AUTHOR]

While the constrained minimal supersymmetric standard model (CMSSM) with universal gaugino masses, m, scalar masses, m, and A-terms, A, defined at some high energy scale (usually taken to be the GUT scale) is motivated by general features of supergravity models, it does not carry all of the constraints imposed by minimal supergravity (mSUGRA). In particular, the CMSSM does not impose a relation between the trilinear and bilinear soft supersymmetry breaking terms, B= A− m, nor does it impose the relation between the soft scalar masses and the gravitino mass, m= m. As a consequence, tan β is computed given values of the other CMSSM input parameters. By considering a Giudice-Masiero (GM) extension to mSUGRA, one can introduce new parameters to the Kähler potential which are associated with the Higgs sector and recover many of the standard CMSSM predictions. However, depending on the value of A, one may have a gravitino or a neutralino dark matter candidate. We also consider the consequences of imposing the universality conditions above the GUT scale. This GM extension provides a natural UV completion for the CMSSM. [ABSTRACT FROM AUTHOR]

In the context of phenomenological models in which the soft supersymmetry-breaking parameters of the MSSM become universal at some unification scale, M, above the GUT scale, M, it is possible that all the scalar mass parameters m, the trilinear couplings A and the bilinear Higgs coupling B vanish simultaneously, as in no-scale supergravity. Using these no-scale inputs in a renormalisation-group analysis of the minimal supersymmetric SU(5) GUT model, we pay careful attention to the matching of parameters at the GUT scale. We delineate the region of M, m and tan β where the resurrection of no-scale supergravity is possible, taking due account of the relevant phenomenological constraints such as electroweak symmetry breaking, m, b→ s γ, the neutralino cold dark matter density Ω h and g−2. No-scale supergravity survives in an L-shaped strip of parameter space, with one side having m≳200 GeV, the second (orthogonal) side having M≳5×10 GeV. Depending on the relative signs and magnitudes of the GUT superpotential couplings, these may be connected to form a triangle whose third side is a hypotenuse at larger M, m and tan β, whose presence and location depend on the GUT superpotential parameters. We compare the prospects for detecting sparticles at the LHC in no-scale supergravity with those in the CMSSM and the NUHM. [ABSTRACT FROM AUTHOR]

We show the uniqueness of superpotentials leading to Minkowski vacua of single-field no-scale supergravity models, and the construction of dS/AdS solutions using pairs of these single-field Minkowski superpotentials. We then extend the construction to two- and multifield no-scale supergravity models, providing also a geometrical interpretation. We also consider scenarios with additional twisted or untwisted moduli fields, and discuss how inflationary models can be constructed in this framework. [ABSTRACT FROM AUTHOR]

We present a model for cosmological inflation based on a no-scale supergravity sector with an SU(2, l)/SU(2) X U(l) Kähler potential, a single modulus T, and an inflaton superfield 1 described by a Wess-Zumino model with superpotential parameters (μ., Λ. When T is fixed, this model yields a scalar spectral index ns and a tensor-to-scalar ratio r that are compatible with the Planck measurements for values of Λ ≃ μ/3Mp. For the specific choice Λ = μ/3Mp, the model is a no-scale supergravity realization of the R + R2 Starobinsky model. [ABSTRACT FROM AUTHOR]

A correction to the article "No-Scale Supergravity Realization of the Starobinsky Model of Inflation" that was published in the September 19, 2013 issue is presented.