Next-to-leading resummations in cosmological perturbation theory

TL;DR

This paper extends the resummation techniques in cosmological perturbation theory to include next-to-leading corrections, improving the accuracy of predictions for galaxy surveys.

Contribution

It generalizes existing resummation results by deriving an exact evolution equation that captures next-to-leading corrections at all perturbative orders.

Findings

Next-to-leading corrections modify the propagator by a few percent.

Corrections are significant in the Baryonic Acoustic Oscillation range.

Improved approximations for the Power Spectrum can be derived using these tools.

Abstract

One of the nicest results in cosmological perturbation theory is the analytical resummaton of the leading corrections at large momentum, which was obtained by Crocce and Scoccimarro for the propagator. Using an exact evolution equation, we generalize this result, by showing that a class of next-to-leading corrections can also be resummed at all orders in perturbation theory. The new corrections modify the propagator by a few percent in the Baryonic Acoustic Oscillation range of scales, and therefore cannot be neglected in resummation schemes aiming at an accuracy compatible with future generation galaxy surveys. Similar tools can be employed to derive improved approximations for the Power Spectrum.