الفهرس 
The Standard FRW CosmologyOnly 14 pages are availabe for public view
 |  | from | 178 |  |  |
| | | from | 178 | | |
Abstract
The standard model of cosmology has many successes, such as explaining the expan- sion of the universe. Nevertheless, it fails in describing the causal large scale structure of the universe within the predicted age and the inhomogeneity and anisotropy dis- covered in the CMBR, without including quantum gravity.
On the other hand, on the small scale, the standard model of particle physics is very successful in explaining three of the fundamental forces of nature, namely strong nuclear force, weak force and electromagnetism. However, it is known that the SM is not the ultimate theory on the microscopic scale, since it su ers from some drawbacks. For instance, accounting for the fourth fundamental force of gravity and that it predicts that neutrinos are massless, a statement which was proved to be false by observation of neutrino oscillations. Besides, when we consider the running of the SM at high scale, it breaks down to an unstable Higgs vacuum at ∼ 1012 GeV.
Numerous models were suggested to account for solving the problems of the large scale standard cosmology model as well as the small scale standard model of particle physics. A good example for this is the hybrid in ation model. In this work, we connect both sectors by adding an extra scalar eld to the hybrid in ation model, which in turn improves its predictions and also stabilizes the electroweak vacuum.
We propose a modi cation to the standard hybrid in ation model [84], that con- nects a successful hybrid in ation scenario to the standard model higgs sector, via the electroweak vacuum stability. The proposed model results in an e ective in ation potential of a hilltop-type, with both the trans-Planckian and sub-Planckian in ation regimes are consistent with the recent Planck/BICEP combined results. Reheating via the in ation sector decays to right-handed neutrinos is considered. An upper
bound on the reheating temperature TR <∼ 2 × 1011 (1 × 1013) GeV, for large (small)
eld in ation, will suppress contributions from one-loop quantum corrections to the in ation potential. This may push the neutrino Yukawa couplings to be O(1) and
a ect the vacuum stability. We show that the couplings of the SM Higgs to the in ation sector can guarantee the electroweak vacuum stability up to Planck scale. The so-called hybrid Higgs-in aton model leads to a positive correction for the Higgs quartic coupling at a threshold scale, which is shown to have a very signi cant e ect in stabilizing the electroweak vacuum. We nd that even with O(1) neutrino Yukawa couplings, threshold corrections leave the SM vacuum stability intact.