An analytic approach to baryon acoustic oscillations

TL;DR

This paper revises the fitting formula for the first acoustic peak in the matter power spectrum, improving accuracy by incorporating detailed physics of baryon acoustic oscillations and recombination history.

Contribution

It introduces a new fitting formula for the acoustic peak location that aligns within 5% of numerical results, surpassing previous deviations of up to 20%.

Findings

New fitting formula matches numerical results within 5%.

Recombination history accuracy is crucial for precise BAO modeling.

Physics of recombination and velocity effects are key to understanding BAO features.

Abstract

The fitting formula for the location of the first acoustic peak in the matter power spectrum is revised. We discuss the physics that leads to baryon acoustic oscillations: the recombination history, the tight coupling approximation and the velocity overshoot effect. A new fitting formula is proposed, which is in accordance within 5% with numerical results for a suitable range of cosmological parameters, whereas previous results yield deviations of up to 20%. The crucial improvement turns out to be the accuracy of the recombination history.