Measuring the Hubble Constant Without the Sound Horizon: A New Constraint from DESIConfirmed

by Erik Zaborowski (Ohio State University)

Tuesday Dec 2, 2025, 11:00 AM → 12:30 PM America/Toronto

PI/4-405 - Bob Room (Perimeter Institute for Theoretical Physics)

The Hubble tension, recently reaching as high as 7σ, increasingly presents a challenge to the ΛCDM model. A key question is whether this tension stems from our use of the sound horizon as a standard ruler. In this talk, I will present a new, sub-2% measurement of the Hubble constant (H₀) that is independent of the sound horizon scale, using data from the first data release of the Dark Energy Spectroscopic Instrument (DESI). The analysis employs a power spectrum rescaling technique that marginalizes over the sound horizon information, drawing instead on the matter-radiation equality scale as a standard ruler. Combining DESI’s full-shape galaxy clustering with uncalibrated post-reconstruction BAO and the CMB acoustic scale θ*, along with various external sound horizon-free datasets, results in highly robust constraints that are the most precise to date from LSS. Looking ahead, this measurement offers a new window on beyond-ΛCDM physics and the physical origin of the Hubble tension.