The one-loop matter bispectrum in the Effective Field Theory of Large Scale Structures
- Centro de Estudios de Fisica del Cosmos de Aragon, Plaza San Juan 1, Planta-2, 44001, Teruel (Spain)
- Stanford Institute for Theoretical Physics and Department of Physics, Stanford University, Stanford, CA 94306 (United States)
- Berkeley Center for Cosmological Physics, Department of Physics, University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)
Given the importance of future large scale structure surveys for delivering new cosmological information, it is crucial to reliably predict their observables. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbative scheme to compute the clustering of dark matter in the weakly nonlinear regime in an expansion in k/k{sub NL}, where k is the wavenumber of interest and k{sub NL} is the wavenumber associated to the nonlinear scale. It has been recently shown that the EFTofLSS matches to 1% level the dark matter power spectrum at redshift zero up to k≅ 0.3 h Mpc{sup −1} and k≅ 0.6 h Mpc{sup −1} at one and two loops respectively, using only one counterterm that is fit to data. Similar results have been obtained for the momentum power spectrum at one loop. This is a remarkable improvement with respect to former analytical techniques. Here we study the prediction for the equal-time dark matter bispectrum at one loop. We find that at this order it is sufficient to consider the same counterterm that was measured in the power spectrum. Without any remaining free parameter, and in a cosmology for which k{sub NL} is smaller than in the previously considered cases (σ{sub 8}=0.9), we find that the prediction from the EFTofLSS agrees very well with N-body simulations up to k≅ 0.25 h Mpc{sup −1}, given the accuracy of the measurements, which is of order a few percent at the highest k's of interest. While the fit is very good on average up to k≅ 0.25 h Mpc{sup −1}, the fit performs slightly worse on equilateral configurations, in agreement with expectations that for a given maximum k, equilateral triangles are the most nonlinear.
- OSTI ID:
- 22525241
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2015, Issue 10; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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