Updated bounds on sum of neutrino masses in various cosmological scenarios

摘要

We present strong bounds on the sum of three active neutrino masses (P mν ) using selected cosmological datasets and priors in various cosmological models. We use the following baseline datasets: Cosmic Microwave Background (CMB) temperature data from Planck 2015, Baryon Acoustic Oscillations measurements from SDSS-III BOSS DR12, the newly released Type Ia supernovae (SNe Ia) dataset from Pantheon Sample, and a prior on the optical depth to reionization from 2016 Planck Intermediate results. We constrain cosmological parameters with these datasets with a Bayesian analysis in the background of ΛCDM model with 3 massive active neutrinos. For this minimal ΛCDM + Σ_(mν ) model we find a upper bound of Σ_(mν ) < 0.152 eV at 95% C.L. Adding the high-l polarization data from Planck strengthens this bound to Σ_(mν ) < 0.118 eV, which is very close to the minimum required mass of Σ_(mν) ' 0.1 eV for inverted hierarchy. This bound is reduced to Σ_(mν ) < 0.110 eV when we also vary r, the tensor to scalar ratio (ΛCDM + r + Σ_(mν ) model), and add an additional dataset, BK14, the latest data released from the Bicep-Keck collaboration (which we add only when r is varied). This bound is further reduced to Σ_(mν ) < 0.101 eV in a cosmology with non-phantom dynamical dark energy (w0waCDM + Σ_(mν ) model with w(z) ≥-1 for all z). Considering the w0waCDM + r + Σ_(mν ) model and adding the BK14 data again, the bound can be even further reduced to Σ_(mν ) < 0.093 eV. For the w0waCDM + Σ_(mν ) model without any constraint on w(z), the bounds however relax to Σ_(mν ) < 0.276 eV. Adding a prior on the Hubble constant (H_0 = 73.24 ± 1.74 km/sec/Mpc) from Hubble Space Telescope (HST), the above mentioned bounds further improve to Σ_(mν ) < 0.117 eV, 0.091 eV, 0.085 eV, 0.082 eV, 0.078 eV and 0.247 eV respectively. This substantial improvement is mostly driven by a more than 3σ tension between Planck 2015 and HST measurements of H)0 and should be taken cautio