Cosmology in Extended Parameter Space with DESI Data Release 2 Baryon Acoustic Oscillations: A 2$\ddot{I}ƒ$+ Detection of Nonzero Neutrino Masses with an Update on Dynamical Dark Energy and Lensing Anomaly

Abstract

We obtain constraints in a 12 parameter cosmological model using the recent Dark Energy Spectroscopic Instrument Data Release (DR) 2 Baryon Acoustic Oscillations (BAO) data, combined with cosmic microwave background (CMB) power spectra (Planck Public Release, PR, 4) and lensing (Planck PR4 + Atacama Cosmology Telescope (ACT) Data Release (DR) 6) data, uncalibrated Type Ia Supernovae (SNe) data from Pantheon+ and Dark Energy Survey (DES) Year 5 (DESY5) samples, and Weak Lensing (WL: DES Year 1) data. The cosmological model consists of six $\hat{I}›$CDM parameters, and additionally, the dynamical dark energy parameters ($w_0$, $w_a$), the sum of neutrino masses ($\sum m_{\hat{I}}½$), the effective number of non-photon radiation species ($N_{\mathrm{eff}}$), the scaling of the lensing amplitude ($A_{\mathrm{lens}}$), and the running of the scalar spectral index ($\hat{I}{\pm }_s$). Our major findings are the following: i) With CMB+BAO+DESY5+WL, we obtain the first 2$\ddot{I}ƒ$+ detection of a nonzero $\sum m_{\hat{I}}½=0.19_{-0.18}^{+0.15}$ eV (95%). Replacing DESY5 with Pantheon+ still yields a $\sim$1.9$\ddot{I}ƒ$ detection. ii) The cosmological constant lies at the edge of the 95% contour with CMB+BAO+Pantheon+, but is excluded at 2$\ddot{I}ƒ$+ with DESY5, leaving evidence for dynamical dark energy dataset-dependent and inconclusive. iii) With CMB+BAO+SNe+WL, $A_{\mathrm{lens}}=1$ is excluded at $>2\ddot{I}ƒ$, while it remains consistent with unity without WL data - suggesting that the existence of lensing anomaly with Planck PR4 likelihoods may depend on non-CMB datasets. iv) The Hubble tension persists at 3.6-4.2$\ddot{I}ƒ$ with CMB+BAO+SNe; WL data has minimal impact.

12 pages, 6 figures. V3 closely matches the published ApJL version; the published paper is open access. V4 corrects minor typos in Table 2: the lower 1-sigma errors on A_lens in columns 1, 2, and 4 are 0.054, 0.050, and 0.052, not 0.54, 0.50, and 0.52. This is purely typographical and does not affect the analyses, results, or conclusions

References in corpus (1)

• Assessing observational constraints on dark energy

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