Cosmological Preference for a Positive Neutrino Mass at 2.7$sigma$: A Joint Analysis of DESI DR2, DESY5, and DESY1 Data
Guo-Hong Du, Tian-Nuo Li, Peng-Ju Wu, Jing-Fei Zhang, Xin Zhang
arXiv:2507.16589v2 Announce Type: replace
Abstract: Neutrinos and dark energy (DE) have entered a new era of investigation, as the latest DESI baryon acoustic oscillation measurements tighten the constraints on the neutrino mass and suggest that DE may be dynamical rather than a cosmological constant. {In this work, we obtain a high-confidence measurement of the neutrino mass within a dynamical DE framework. A joint analysis of DESI DR2, cosmic microwave background, DESY5 supernova, and DESY1 weak lensing data yields a total neutrino mass of $sum m_nu = 0.098^{+0.016}_{-0.037},mathrm{eV}$, indicating a measurement for a non-zero, positive neutrino mass at the $2.7sigma$ level within the $w_0w_a$CDM framework. This high-confidence measurement is driven mainly by these factors: (i) the DESI’s preference for a dynamical DE with its equation of state evolving from $w -1$ at late times, thus leading to a larger neutrino mass; (ii) treating $N_{mathrm{eff}}$ as a free parameter together with the inclusion of weak lensing data, which likewise allows for an increased neutrino mass.} In future, even higher-confidence measurements of neutrino mass are expected with stronger preferences for dynamical DE in light of more complete DESI data releases.arXiv:2507.16589v2 Announce Type: replace
Abstract: Neutrinos and dark energy (DE) have entered a new era of investigation, as the latest DESI baryon acoustic oscillation measurements tighten the constraints on the neutrino mass and suggest that DE may be dynamical rather than a cosmological constant. {In this work, we obtain a high-confidence measurement of the neutrino mass within a dynamical DE framework. A joint analysis of DESI DR2, cosmic microwave background, DESY5 supernova, and DESY1 weak lensing data yields a total neutrino mass of $sum m_nu = 0.098^{+0.016}_{-0.037},mathrm{eV}$, indicating a measurement for a non-zero, positive neutrino mass at the $2.7sigma$ level within the $w_0w_a$CDM framework. This high-confidence measurement is driven mainly by these factors: (i) the DESI’s preference for a dynamical DE with its equation of state evolving from $w -1$ at late times, thus leading to a larger neutrino mass; (ii) treating $N_{mathrm{eff}}$ as a free parameter together with the inclusion of weak lensing data, which likewise allows for an increased neutrino mass.} In future, even higher-confidence measurements of neutrino mass are expected with stronger preferences for dynamical DE in light of more complete DESI data releases.