Linking Starobinsky-Type Inflation in no-Scale Supergravity to MSSM
  A novel realization of the Starobinsky inflationary model within a moderate
extension of the Minimal Supersymmetric Standard Model (MSSM) is presented. The
proposed superpotential is uniquely determined by applying a continuous R and a
Z_2 discrete symmetry, whereas the Kahler potential respects a no-scale-type
SU(54,1)/SU(54)x U(1)_R x Z_2 symmetry too. The inflaton is identified with a
Higgs-like modulus whose the vacuum expectation value controls the
gravitational strength. Thanks to a strong enough coupling (with a parameter cT
involved) between the inflaton and the Ricci scalar curvature, inflation can be
attained even for subplanckian values of the inflaton with cT>76 and the
corresponding effective theory being valid up to the Planck scale. The
inflationary observables turn out to be in agreement with the current data and
the inflaton mass is predicted to be 3x10^13 GeV. At the cost of a relatively
small superpotential coupling constant, the model offers also a resolution to
the mu problem of the MSSM. Supplementing MSSM by three right-handed neutrinos
we show that spontaneously arising couplings between the inflaton and the
particle content of MSSM not only ensure a sufficiently low reheating
temperature but also support a scenario of non-thermal leptogenesis
consistently with the neutrino oscillation parameters for gravitino heavier
than about 10^4 GeV.
