Implementing Hilltop F-term Hybrid Inflation in Supergravity
  F-term hybrid inflation (FHI) of the hilltop type can generate a scalar
spectral index, ns, in agreement with the fitting of the seven-year Wilkinson
microwave anisotropy probe data by the standard power-law cosmological model
with cold dark matter and a cosmological constant, LambdaCDM. We investigate
the realization of this type of FHI by using quasi-canonical Kahler potentials
with or without the inclusion of extra hidden-sector fields. In the first case,
acceptable results can be obtained by constraining the coefficients of the
quadratic and/or quartic supergravity correction to the inflationary potential
and therefore a mild tuning of the relevant term of the Kahler potential is
unavoidable. Possible reduction of ns without generating maxima and minima of
the potential on the inflationary path is also possible in a limited region of
the available parameter space. The tuning of the terms of the Kahler potential
can be avoided with the adoption of a simple class of string-inspired Kahler
potentials for the hidden-sector fields which ensures a resolution to the eta
problem of FHI and allows acceptable values for the spectral index,
constraining the coefficient of the quartic supergravity correction to the
inflationary potential. Performing a four-point test of the analyzed models, we
single out the most promising of these.
