Loop Corrections in Nonlinear Cosmological Perturbation Theory. II. Two‐Point Statistics and Self‐Similarity

We calculate the lowest order nonlinear contributions to the power spectrum, two-point correlation function, and smoothed variance of the density eld, for Gaussian initial conditions and scale-free initial power spectra, P(k) D kn. These results extend and, in some cases, correct previous work in the literature on cosmological perturbation theory. Comparing with the scaling behavior observed in N-body simulations, we nd that the validity of nonlinear perturbation theory depends strongly on the spectral index n.