Massive Gauge-flation
  Gauge-flation model at zeroth order in cosmological perturbation theory offers an interesting scenario for realizing inflation within a particle physics context, allowing us to investigate interesting possible connections between inflation and the subsequent evolution of the Universe. Difficulties, however, arise at the perturbative level, thus motivating a modification of the original model. In order to agree with the latest Planck observations, we modify the model such that the new dynamics can produce a relation between the spectral index $n_{s}$ and the tensor-to-scalar ratio $r$ allowed by the data. By including an identical mass term for each of the fields of the system, we find interesting dynamics leading to slow-roll inflation of the right length. The presence of the mass term has the potential to modify the $n_{s}$ vs. $r$ relation so as to agree with the data. As a first step, we study the model at zeroth order in cosmological perturbation theory, finding the conditions required for slow-roll inflation and the number of e-foldings of inflation. Numerical solutions are used to explore the impact of the mass term. We conclude that the massive version of Gauge-flation offers a viable inflationary model. 
Carlos M. Nieto (1,2), Yeinzon Rodriguez (2,3,4) ((1) Scuola   Internazionale Superiore di Studi Avanzati, (2) The Abdus Sal...
gr-qc astro-ph.CO hep-ph