A Model for the Squeezed Bispectrum in the Non-Linear Regime

Abstract

We present a model for the squeezed dark matter bispectrum, where the short modes are deep in the non-linear regime. We exploit the consistency relations for large-scale structures combined with a response function approach to write the squeezed bispectrum in terms of a few unknown functions of the short modes. We provide an ansatz for a fitting function for these response functions, checking that the resulting model is reliable when compared to the one-loop squeezed bispectrum. We then test the model against measured bispectra from numerical simulations for short modes ranging between $k \sim 0.1 \, h/$Mpc, and $k \sim 0.7 \, h/$Mpc at redshift $z=0$. To evaluate the goodness of the fit of our model we implement a non-Gaussian covariance and find agreement within $1$-$\sigma$ standard deviation of the simulated data.