Characterising the matter bispectrum of large-scale structure - a three dimensional comparison between models and simulations

The main perturbative models for the matter bispectrum of LSS are investigated, finding that the effective field theory extends the range of validity furthest into the nonlinear regime. The divergences appearing in loop integrals are eliminated and thus the 2-loop matter bispectrum in the renormalized perturbation theory is determined. A significant deficit of power is found in the halo model on intermediate scales, which worsens as the redshift is increased. A strong squeezed signal is determined on these scales from numerical simulations that is underestimated in the halo model. Finally, a  three-shape model based on the fundamental shapes of the halo model is proposed. This model provides an accurate description for the simulated bispectrum for k<8 h/Mpc for z<=2 by suitable calibration.