On the $2^\text{nd}$ feature of the matter two-point function

TL;DR

This paper predicts a second feature in the matter two-point correlation function caused by baryon-baryon correlations, but it is unlikely to be detected with current galaxy surveys like SKA.

Contribution

It identifies a new baryon-related feature in the matter correlation function and analyzes its detectability with upcoming surveys.

Findings

A second feature exists at twice the acoustic peak's distance.

Standard surveys like SKA are unlikely to detect this feature.

The feature is linked to baryon-baryon correlations in the early universe.

Abstract

We point out the existence of a second feature in the matter two-point function, besides the acoustic peak, due to the baryon-baryon correlation in the early universe and positioned at twice the distance of the peak. We discuss how the existence of this feature is implied by the well-known heuristic argument that explains the baryon bump in the correlation function. A standard $\chi^2$ analysis to estimate the detection significance of the second feature is mimicked. We conclude that for realistic values of the baryon density, an SKA-like galaxy survey will not be able to detect this feature with standard correlation function analysis.