The road to $H_0$, $Ω_m$, and $w$ with a global neutrino-telescope network

Abstract

The newly measured correlation between the neutrino and X-ray luminosities of Seyfert galaxies has yielded the first neutrino-based measurement of the Hubble constant. Building on this result, we forecast the reach of a global neutrino-telescope network by 2030, utilizing full-sky IceCube exposures combined with KM3NeT-ARCA and Baikal-GVD. We find that this 2030 configuration sharpens the neutrino-measured Hubble constant from today's $H_0 = 66^{+44}_{-37}$ to $H_0 =66^{+15}_{-13}$ km s$^{-1}$ Mpc$^{-1}$. Additionally, we project that the disk-corona slope of the neutrino X-ray luminosity relation ($L_ν\propto L_X^β$) will reach $β=0.72\pm0.04$, enabling a $\geq \!5σ$ exclusion of the calorimetric value $β=1$. Finally, we show that, if a high-redshift population of neutrino sources, such as JWST's "little red dots," is identified and obeys the same luminosity relation, we can obtain a new independent measurement of the matter density $Ω_m$ and the dark energy equation-of-state parameter $w$.