Polonyi Inflation
  Spontaneously broken supersymmetry (SUSY) and a vanishingly small
cosmological constant imply that R symmetry must be spontaneously broken at low
energies. Based on this observation, we suppose that, in the sector responsible
for low-energy R symmetry breaking, a discrete R symmetry remains preserved at
high energies and only becomes dynamically broken at relatively late times in
the cosmological evolution, i.e., after the dynamical breaking of SUSY. Prior
to R symmetry breaking, the Universe is then bound to be in a quasi-de Sitter
phase---which offers a dynamical explanation for the occurrence of cosmic
inflation. This scenario yields a new perspective on the interplay between SUSY
breaking and inflation, which neatly fits into the paradigm of high-scale SUSY:
inflation is driven by the SUSY-breaking vacuum energy density, while the
chiral field responsible for SUSY breaking, the Polonyi field, serves as the
inflaton. Because R symmetry is broken only after inflation, slow-roll
inflation is not spoiled by otherwise dangerous gravitational corrections in
supergravity. We illustrate our idea by means of a concrete example, in which
both SUSY and R symmetry are broken by strong gauge dynamics and in which
late-time R symmetry breaking is triggered by a small inflaton field value. In
this model, the scales of inflation and SUSY breaking are unified; the
inflationary predictions are similar to those of F-term hybrid inflation in
supergravity; reheating proceeds via gravitino decay at temperatures consistent
with thermal leptogenesis; and the sparticle mass spectrum follows from pure
gravity mediation. Dark matter consists of thermally produced winos with a mass
in the TeV range.
