Time-Sliced Perturbation Theory II: Baryon Acoustic Oscillations and Infrared Resummation

TL;DR

This paper applies time-sliced perturbation theory to accurately model the nonlinear infrared effects on baryon acoustic oscillations, providing explicit resummation formulas and validating results against N-body simulations.

Contribution

It introduces a systematic resummation method within TSPT for BAO analysis, avoiding uncontrolled approximations and enabling precise predictions of peak shifts.

Findings

Resummed matter power spectrum matches N-body data at BAO scales.

Explicit formulas derived for power spectrum and bispectrum.

Reliable assessment of BAO peak shift due to nonlinear effects.

Abstract

We use time-sliced perturbation theory (TSPT) to give an accurate description of the infrared non-linear effects affecting the baryonic acoustic oscillations (BAO) present in the distribution of matter at very large scales. In TSPT this can be done via a systematic resummation that has a simple diagrammatic representation and does not involve uncontrollable approximations. We discuss the power counting rules and derive explicit expressions for the resummed matter power spectrum up to next-to leading order and the bispectrum at the leading order. The two-point correlation function agrees well with N-body data at BAO scales. The systematic approach also allows to reliably assess the shift of the baryon acoustic peak due to non-linear effects.