On the EFT of Large Scale Structures in Redshift Space

TL;DR

This paper advances the Effective Field Theory approach to modeling redshift space distortions in large-scale structures, incorporating baryonic effects, primordial non-Gaussianity, and IR-resummation, and compares predictions with simulations.

Contribution

It generalizes counterterms to include baryonic physics and non-Gaussianity, and evaluates IR-resummation in redshift space, improving theoretical predictions for large-scale structure analysis.

Findings

IR-resummation correctly reproduces the BAO peak

Theory matches simulation data to percent level up to certain scales

Inclusion of additional counterterms improves k-range accuracy

Abstract

We further develop the description of redshift space distortions within the Effective Field Theory of Large Scale Structures. First, we generalize the counterterms to include the effect of baryonic physics and primordial non-Gaussianity. Second, we evaluate the IR-resummation of the dark matter power spectrum in redshift space. This requires us to identify a controlled approximation that makes the numerical evaluation straightforward and efficient. Third, we compare the predictions of the theory at one loop with the power spectrum from numerical simulations up to $\ell=6$. We find that the IR-resummation allows us to correctly reproduce the BAO peak. The $k$-reach, or equivalently the precision for a given $k$, depends on additional counterterms that need to be matched to simulations. Since the non-linear scale for the velocity is expected to be longer than the one for the overdensity, we consider a minimal and a non-minimal set of counterterms. The quality of our numerical data makes it hard to firmly establish the performance of the theory at high wavenumbers. Within this limitation, we find that the theory at redshift $z=0.56$ and up to $\ell=2$ matches the data to percent level approximately up to $k \sim 0.13 \, h { \rm Mpc^{-1}}$ or $k \sim 0.18 \, h { \rm Mpc^{-1}}$, depending on the number of counterterms used, with potentially large improvement over former analytical techniques.