Inflation beyond T-models and primordial B-modes
  We describe extended theories which shares the gauge transformation symmetry of the T-models, and takes the T-models as well as Starobinsky model as special cases. We derive a general relation between the two slow-roll parameters, and find that a large class of models can be embedded. Such models include more general Starobinsky-like inflation as well as the chaotic inflation with a large tensor-to-scalar ratio consistent with the BICEP2 result. 
Yi-Fu Cai, Jinn-Ouk Gong, Shi Pi
hep-th astro-ph.CO gr-qc