$H_0$ Without the Sound Horizon (or Supernovae): A 2% Measurement in DESI DR1

TL;DR

This paper presents a highly precise, sound horizon-independent measurement of the Hubble constant using DESI DR1 data, innovative rescaling techniques, and multiple datasets, achieving better than 2% accuracy.

Contribution

It introduces a novel method to measure H_0 without relying on the sound horizon scale, combining uncalibrated BAO and CMB data for robust results.

Findings

Achieved a 2% level measurement of H_0 independent of the sound horizon.

Demonstrated consistency across multiple datasets and analysis methods.

Provided some of the most precise sound horizon-independent H_0 constraints to date.

Abstract

The sound horizon scale $r_s$ is a key source of information for early-time $H_0$ measurements, and is therefore a common target of new physics proposed to solve the Hubble tension. We present a sub-2% measurement of the Hubble constant that is independent of this scale, using data from the first data release of the Dark Energy Spectroscopic Instrument (DESI DR1). Building on previous work, we remove dependency on the sound horizon size using a heuristic rescaling procedure at the power spectrum level. A key innovation is the inclusion of \emph{uncalibrated} (agnostic to $r_s$) post-reconstruction BAO measurements from DESI DR1, as well as using the CMB acoustic scale $\theta_*$ as a high-redshift anchor. Uncalibrated type-Ia supernovae are often included as an independent source of $\Omega_m$ information; here we demonstrate the robustness of our results by additionally considering two supernova-independent alternative datasets. We find somewhat higher values of $H_0$ relative to our previous work: $69.2^{+1.3}_{-1.4}$, $70.3^{+1.4}_{-1.2}$, and $69.6^{+1.3}_{-1.8}\,{\rm km\,s^{-1}\,Mpc^{-1}}$ respectively when including measurements from i) Planck/ACT CMB lensing $\times$ unWISE galaxies, ii) the DES Year 3 6$\times$2pt analysis, and iii) Planck/ACT CMB lensing + the DES Year 5 supernova analysis. These remarkably consistent constraints achieve better than 2% precision; they are among the most stringent sound horizon-independent measurements from LSS to date, and provide a powerful avenue for probing the origin of the Hubble tension.