Three-point correlation function in the quasilinear regime

Using the second-order Eulerian perturbation theory (SEPT), we study the three-point correlation function $\zeta$ in the quasilinear regime for the SCDM, LCDM and MDM models, with the interesting result that these three models have distinctive three-point correlation functions. We test this SEPT prediction using a large set of high-resolution N-body simulations. The N-body results show that the SEPT prediction for $\zeta$ is not accurate even in the quasilinear regime ($r\la 10 \mpc$), in contrast to previous N-body tests on the skewness. However, similar to the perturbation theory, our N-body results still predict a strong dependence of the three-point correlation on the triangle shape which is observable in the distribution of galaxies if the galaxies trace the distribution of the underlying mass