Spectral index and running of gNL from an isocurvature scalar field

It is possible that the primordial non-Gaussianity is dominated by the higher order terms, such as that set by gNL, not fNL. In this paper we re-derive the spectral index and work out the running of gNL from a single isocurvature scalar field. The scale dependences of non-Gaussianity parameters are detectable if the mass of isocurvature field is not too small compared to the Hubble parameter during inflation. In addition, we also apply our results to investigate the curvaton model with near quadratic potential in detail