Consistency of DES and DESI distances and the Standard Cosmological Model
Richard Watkins, Cordelia Trueax, Hume A. Feldman
arXiv:2606.18374v1 Announce Type: new
Abstract: We test the consistency of the cosmic distance-redshift relation inferred from the cosmic microwave background (CMB), the Dark Energy Spectroscopic Instrument (DESI) baryon acoustic oscillation measurements, and the Dark Energy Survey (DES) Type Ia supernovae within the framework of flat $Lambda$CDM. DESI recovers the CMB-constrained parameter combination $(r_d h)(Omega_m/0.3)^{0.4}$ with sub-percent precision, demonstrating excellent agreement between BAO measurements at $z sim 1$ and the acoustic scale at recombination. Imposing the CMB constraint yields an estimate of $Omega_m$ that is slightly lower than, but only in mild tension with, the Planck value. The high-redshift DES supernova sample is well described by the standard cosmological model, whereas the current low-redshift anchor sample exhibits a systematic offset of $sim 0.05$ mag that drives much of the apparent preference for evolving dark energy. Preliminary data from the Dark Energy Bedrock All-Sky Supernova Program (DEBASS) do not show this offset, suggesting that unresolved low-redshift systematics may account for the discrepancy. These results suggest that a single flat $Lambda$CDM model accurately describes the distance-redshift relation from the local Universe to recombination, placing increasingly stringent constraints on new-physics explanations of the Hubble tension.arXiv:2606.18374v1 Announce Type: new
Abstract: We test the consistency of the cosmic distance-redshift relation inferred from the cosmic microwave background (CMB), the Dark Energy Spectroscopic Instrument (DESI) baryon acoustic oscillation measurements, and the Dark Energy Survey (DES) Type Ia supernovae within the framework of flat $Lambda$CDM. DESI recovers the CMB-constrained parameter combination $(r_d h)(Omega_m/0.3)^{0.4}$ with sub-percent precision, demonstrating excellent agreement between BAO measurements at $z sim 1$ and the acoustic scale at recombination. Imposing the CMB constraint yields an estimate of $Omega_m$ that is slightly lower than, but only in mild tension with, the Planck value. The high-redshift DES supernova sample is well described by the standard cosmological model, whereas the current low-redshift anchor sample exhibits a systematic offset of $sim 0.05$ mag that drives much of the apparent preference for evolving dark energy. Preliminary data from the Dark Energy Bedrock All-Sky Supernova Program (DEBASS) do not show this offset, suggesting that unresolved low-redshift systematics may account for the discrepancy. These results suggest that a single flat $Lambda$CDM model accurately describes the distance-redshift relation from the local Universe to recombination, placing increasingly stringent constraints on new-physics explanations of the Hubble tension.

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