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Neutrino Mass Bounds in the era of Tension Cosmology

The measurements of Cosmic Microwave Background anisotropies made by the Planck satellite provide extremely tight upper bounds on the total neutrino mass scale ($Σm_ν<0.26 eV$ at $95\%$ C.L.). However, as recently discussed in the literature, Planck data show anomalies that could affect this result. Here we provide new constraints on neutrino masses using the recent and complementary CMB measurements from the Atacama Cosmology Telescope DR4 and the South Polar Telescope SPT-3G experiments. We found that both the ACT-DR4 and SPT-3G data, when combined with WMAP, mildly suggest a neutrino mass with $Σm_ν=0.68 \pm 0.31$ eV and $Σm_ν=0.46_{-0.36}^{+0.14}$ eV at $68 \%$ C.L, respectively. Moreover, when CMB lensing from the Planck experiment is included, the ACT-DR4 data now indicates a neutrino mass above the two standard deviations, with $Σm_ν=0.60_{-0.50}^{+0.44}$ eV at $95 \%$, while WMAP+SPT-3G provides a weak upper limit of $Σm_ν<0.37$ eV at $68 \%$ C.L.. Interestingly, these results are consistent with the Planck CMB+Lensing constraint of $Σm_ν = 0.41_{-0.25}^{+0.17}$ eV at $68 \%$ C.L. when variation in the $A_{\rm lens}$ parameter are considered. We also show that these indications are still present after the inclusion of BAO or SN-Ia data in extended cosmologies that are usually considered to solve the so-called Hubble tension. A combination of ACT-DR4, WMAP, BAO and constraints on the Hubble constant from the SH0ES collaboration gives $Σm_ν=0.39^{+0.13}_{-0.25}$ eV at $68 \%$ C.L. in extended cosmologies. We conclude that a total neutrino mass above the $0.26$ eV limit still provides an excellent fit to several cosmological data and that future data must be considered before safely ruling it out.