16328111
Supersymmetric hybrid inflation redux
Abstract We discuss the important role played during inflation by one of the soft supersymmetry breaking terms in the inflationary potential of supersymmetric hybrid inflation models. With minimal Kahler potential, the inclusion of this term allows the prediction for the scalar spectral index to agree with the value n s = 0.963 − 0.015 + 0.014 found by WMAP5. In the absence of this soft term, and by taking into account only radiative and supergravity corrections, it is well known that n s ⩾ 0.985 . This same soft term has previously been shown to play a key role in resolving the MSSM μ problem. The tensor to scalar ratio r is quite small in these models, taking on values r ⩽ 10 − 5 in the WMAP5 2 σ range of n s .
119269294
Simplified smooth inflation with observable gravity waves
We consider a simplified version of supersymmetric smooth hybrid inflation which contains a single ultraviolet cutoff ${m}_{P}=2.4\ifmmode\times\else\texttimes\fi{}{10}^{18}\text{ }\text{ }\mathrm{GeV}$, instead of the two cutoffs ${m}_{P}$ and ${M}_{*}\ensuremath{\sim}\mathrm{\text{few}}\ifmmode\times\else\texttimes\fi{}{10}^{17}\text{ }\text{ }\mathrm{GeV}$ that are normally employed. With global supersymmetry the scalar spectral index ${n}_{s}\ensuremath{\simeq}0.97$, which is in very good agreement with the WMAP observations. With a nonminimal K\"ahler potential, the supergravity version of the model is compatible with the current central values of ${n}_{s}$ and also yields potentially observable gravity waves (tensor to scalar ratio $r\ensuremath{\lesssim}0.02$).
118648696
Minimal supersymmetric hybrid inflation, flipped SU(5) and proton decay
Abstract Minimal supersymmetric hybrid inflation utilizes a canonical Kahler potential and a renormalizable superpotential which is uniquely determined by imposing a U(1) R -symmetry. In computing the scalar spectral index n s we take into account modifications of the tree level potential caused by radiative and supergravity corrections, as well as contributions from the soft supersymmetry breaking terms with a negative soft mass-squared term allowed for the inflaton. All of these contributions play a role in realizing n s values in the range 0.96–0.97 preferred by WMAP. The U(1) R -symmetry plays an important role in flipped SU ( 5 ) by eliminating the troublesome dimension five proton decay. The proton decays into e + π 0 via dimension six operators arising from the exchange of superheavy gauge bosons with a lifetime of order 10 34 – 10 36 years.
119236672
Red spectral tilt and observable gravity waves in shifted hybrid inflation
We consider supersymmetric shifted hybrid inflation models with a red tilted scalar spectral index n_s in agreement with the WMAP 7-yr central value. If non-minimal 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.
119213797
Tensor to Scalar Ratio in Non-Minimal $\phi^4$ Inflation
We reconsider nonminimal λφ 4 chaotic inflation which includes the gravitational coupling term ξℜφ 2 , where φ denotes a gauge singlet inflaton field and ℜ is the Ricci scalar. For ξ ≫ 1, we require, following recent discussions, that the energy scale λ 1/4mP/√ξ for inflation should not exceed the effective UV cutoff scale m P /ξ, where m P denotes the reduced Planck scale. The predictions for the tensor-to-scalar ratio r and the scalar spectral index n s are found to lie within the Wilkinson Microwave Anisotropy Probe 1-σ bounds for 10 -12 ≲ λ ≲ 10 -4 and 10 -3 ≲ ξ ≲ 10 2 . In contrast, the corresponding predictions of minimal λφ 4 chaotic inflation lie outside the Wilkinson Microwave Anisotropy Probe 2-σ bounds. We also find that r ≳ 0.002, provided the scalar spectral index n s ≥ 0.96. In estimating the lower bound on r, we take into account possible modifications due to quantum corrections of the tree level inflationary potential.
119273809
Higgs inflation, quantum smearing, and the tensor to scalar ratio
In cosmic inflation driven by a scalar gauge singlet field with a tree level Higgs potential, the scalar to tensor ratio r is estimated to be larger than 0.036, provided the scalar spectral index n{sub s{>=}}0.96. We discuss quantum smearing of these predictions arising from the inflaton couplings to other particles such as grand unified theory scalars, and show that these corrections can significantly decrease r. However, for n{sub s{>=}}0.96, we obtain r{>=}0.02 which can be tested by the Planck satellite.
118474086
Higgs masses and electroweak precision observables in the lepton-flavor-violating MSSM
The work of S. H. was partially supported by CICYT (grant FPA 2010–22163-C02-01). S. H. and M. R. were supported by the Spanish MICINN’s Consolider-Ingenio 2010 Programme under grant MultiDark CSD2009-00064.