Hilltop inflation with preinflation from coupling to matter fields
  We propose a class of models of supersymmetric hilltop inflation (also called
"new inflation") where the initial conditions of the inflaton close to the
hilltop are generated through "matter field preinflation". This is achieved via
a coupling term between the inflaton and matter fields (i.e. Standard Model
fields or a right-handed neutrino). The same coupling also opens up a decay
channel for the inflaton into Standard Model fields, which allows efficient
reheating of the universe. We discuss the multifield dynamics of the inflaton
and matter fields during inflation using the delta N formalism and show under
which conditions the model effectively reduces to single-field hilltop
inflation during the last 60 e-folds. We also study perturbative reheating
through the matter-inflaton coupling for a specific example where the matter
field is identified with a right-handed (s)neutrino, and demonstrate that in
this case the model can generate the observed baryon asymmetry through
nonthermal leptogenesis.
