Modeling of weak lensing statistics. I. Power spectrum and bispectrum
  We investigate the performance of an analytic model of the 3D matter
distribution, which combines perturbation theory with halo models, for
weak-lensing statistics. We compare our predictions for the weak-lensing
convergence power spectrum and bispectrum with numerical simulations and
fitting formulas proposed in previous works. We find that this model provides
better agreement with simulations than published fitting formulas. This shows
that building on systematic and physically motivated models is a promising
approach. Moreover, this makes explicit the link between the weak-lensing
statistics and the underlying properties of the 3D matter distribution, as a
function of scale $\ell$. Thus, we obtain the contributions to the lensing
power spectrum and bispectrum that arise from perturbative terms (complete up
to one-loop) and nonperturbative terms (e.g., "1-halo" term). Finally, we show
that this approach recovers the dependence on cosmology (for realistic
scenarios).
