The R-axion and non-Gaussianity
  We study cosmological implications of an R-axion, a pseudo Nambu-Goldstone
boson associated with spontaneous breaking of an U(1)_R symmetry, focusing on
its quantum fluctuations generated during inflation. We show that, in the
anomaly mediation, the R-axion decays into a pair of gravitinos, which
eventually decay into the visible particles producing the neutralino LSP. As a
result, the quantum fluctuations of the R-axion are inherited by the cold dark
matter isocurvature density perturbation with potentially large
non-Gaussianity. The constraints on the inflation scale and the initial
misalignment are derived.
