Non-Abelian gauge field inflation

In A. Maleknejad and M. M. Sheikh-Jabbari, arXiv: 1102. 1513. we introduced an inflationary scenario, non-Abelian gauge field inflation or gauge-flation for short, in which slow-roll inflation is driven by non-Abelian gauge field minimally coupled to gravity. We present a more detailed analysis, both numerical and analytical, of the gauge-flation. By studying the phase diagrams of the theory, we show that getting enough number of e-folds during a slow-roll inflation is fairly robust to the choice of initial gauge field values. In addition, we present a detailed analysis of the cosmic perturbation theory in gauge-flation which has many special and interesting features compared the standard scalar-driven inflationary models. The specific gauge-flation model we study in this paper has two parameters, a cutoff scale and the gauge coupling g. Fitting our results with the current cosmological data fixes 10H10^15 GeV (H is the Hubble parameter) and g10^-4, which are in the natural range of parameters in generic particle physics beyond standard models. Our model also predicts a tensor-to-scalar ratio r>0. 05, in the range detectable by the Planck satellite.