http://arxiv.org/abs/1602.07197
The appealing properties of the Gauge-flation model at zeroth order in cosmological perturbation theory constitute a step ahead at cementing inflation on solid particle physics foundations; this, in turn, allows us to have an interesting connection between inflation and the physics of the subsequent evolution of the Universe. However, there are issues at the perturbative level which suggest a modification to the original model. As we want to be in agreement with the latest observations of Planck, we modify the model such that the new dynamics could produce a relation between the spectral index $n_{s}$ and the tensor-to-scalar ratio $r$ in agreement with the allowed parameter window. By including an identical mass term for each of the fields composing the system, we find an interesting dynamics among all the terms in the Lagrangian such that a successful inflationary period is still reproduced. It would indeed be the mass term the responsible for the expected successful modification of the $n_{s}$ vs. $r$ relation. As a first step, we study in this paper the model at zeroth order in cosmological perturbation theory, finding out the conditions for slow-roll inflation and an expression for the final amount of inflation as a function of the mass term. The numerical solution clearly reveals the impact of the mass term and leads us to conclude that the Gauge-flation, in its massive version, is still a good model that describes the inflationary evolution of the Universe.
C. Nieto and Y. Rodriguez
Wed, 24 Feb 16
19/48
Comments: LaTeX file in ws-mpla style, 18 pages, 22 figures
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