I’m currently working in collaboration with John Ellis, Keith Olive, Dimitri Nanopoulos and Natsumi Nagata on an embedding of Starobinsky inflation in a no-scale supersymmetric flipped-SU(5) model. The challenge is to relate the inflationary epoch with lower scale phenomenology; as demonstrated in our previous work with SO(10), Cosmic Microwave Background observables such as the scalar tilt and the tensor-to-scalar ratio can be directly linked to the masses of the Standard Model neutrinos. Depicted in the figure is a snapshot of the calculation of the inflaton decay rate to scalars; as in supersymmetric models a copious amount of gravitinos can be produced during reheating, the observed Dark Matter abundance will place constraints on the Yukawa couplings of the model.
A few references:
I. Antoniadis, J. R. Ellis, J. S. Hagelin and D. V. Nanopoulos, Supersymmetric Flipped SU(5) Revitalized, Phys. Lett. B 194, 231 (1987).
J. R. Ellis, D. V. Nanopoulos and K. A. Olive, Flipped heavy neutrinos: From the solar neutrino problem to baryogenesis, Phys. Lett. B 300, 121 (1993).
Our results have been published as
J. Ellis, M. A. G. Garcia, N. Nagata, D. V. Nanopoulos and K. A. Olive, Starobinsky-like Inflation, Supercosmology and Neutrino Masses in No-Scale Flipped SU(5), JCAP 1707, 006 (2017)