On the Bispectra of Very Massive Tracers in the Effective Field Theory of Large-Scale Structure

TL;DR

This paper investigates the impact of one-loop corrections and higher-derivative biases on the bispectra of massive tracers within the Effective Field Theory of Large-Scale Structure, finding that higher-derivative biases dominate as the main correction.

Contribution

It demonstrates that higher-derivative biases are the primary correction to bispectra across a wide range of tracer masses, with one-loop contributions providing limited perturbative reach enhancement.

Findings

One-loop power spectra and bispectra fit data up to specified scales at percent accuracy.

Higher-order bias coefficients are not significantly enhanced.

Higher-derivative biases are the dominant correction for very massive tracers.

Abstract

The Effective Field Theory of Large-Scale Structure (EFTofLSS) provides a consistent perturbative framework for describing the statistical distribution of cosmological large-scale structure. In a previous EFTofLSS calculation that involved the one-loop power spectra and tree-level bispectra, it was shown that the $k$-reach of the prediction for biased tracers is comparable for all investigated masses if suitable higher-derivative biases, which are less suppressed for more massive tracers, are added. However, it is possible that the non-linear biases grow faster with tracer mass than the linear bias, implying that loop contributions could be the leading correction to the bispectra. To check this, we include the one-loop contributions in a fit to numerical data in the limit of strongly enhanced higher-order biases. We show that the resulting one-loop power spectra and higher-derivative plus leading one-loop bispectra fit the two- and three-point functions respectively up to $k\simeq 0.19\ h\ \rm{Mpc}^{-1}$ and $k\simeq 0.14\ h\ \rm{Mpc}^{-1}$ at the percent level. We find that the higher-order bias coefficients are not strongly enhanced, and we argue that the gain in perturbative reach due to the leading one-loop contributions to the bispectra is relatively small. Thus, we conclude that higher-derivative biases provide the leading correction to the bispectra for tracers of a very wide range of masses.