Strong Bounds on Sum of Neutrino Masses in a 12 Parameter Extended Scenario with Non-Phantom Dynamical Dark Energy ($w(z)\geq -1$)

TL;DR

This paper derives strong constraints on the sum of neutrino masses within an extended cosmological model including non-phantom dynamical dark energy, using diverse observational data sets, and finds that neutrino mass bounds are tighter than in standard models.

Contribution

It provides the first comprehensive analysis of neutrino mass bounds in a 12-parameter extended cosmological scenario with non-phantom dark energy and multiple observational data sets.

Findings

Neutrino mass sum constrained to < 0.123 eV at 95% CL.

Extended parameter space yields tighter neutrino mass bounds than standard models.

Inclusion of HST data suggests a preference for dark radiation, affecting $N_{eff}$.

Abstract

We obtained constraints on a 12 parameter extended cosmological scenario including non-phantom dynamical dark energy (NPDDE) with CPL parametrization. We also include the six $\Lambda$CDM parameters, number of relativistic neutrino species ($N_{\textrm{eff}}$) and sum over active neutrino masses ($\sum m_{\nu}$), tensor-to-scalar ratio ($r_{0.05}$), and running of the spectral index ($n_{run}$). We use CMB Data from Planck 2015; BAO Measurements from SDSS BOSS DR12, MGS, and 6dFS; SNe Ia Luminosity Distance measurements from the Pantheon Sample; CMB B-mode polarization data from BICEP2/Keck collaboration (BK14); Planck lensing data; and a prior on Hubble constant ($73.24\pm1.74$ km/sec/Mpc) from local measurements (HST). We have found strong bounds on the sum of the active neutrino masses. For instance, a strong bound of $\sum m_{\nu} <$ 0.123 eV (95\% C.L.) comes from Planck+BK14+BAO. Although we are in such an extended parameter space, this bound is stronger than a bound of $\sum m_{\nu} <$ 0.158 eV (95\% C.L.) obtained in $\Lambda \textrm{CDM}+\sum m_{\nu}$ with Planck+BAO. Varying $A_{\textrm{lens}}$ instead of $r_{0.05}$ however leads to weaker bounds on $\sum m_{\nu}$. Inclusion of the HST leads to the standard value of $N_{\textrm{eff}} = 3.045$ being discarded at more than 68\% C.L., which increases to 95\% C.L. when we vary $A_{\textrm{lens}}$ instead of $r_{0.05}$, implying a small preference for dark radiation, driven by the $H_0$ tension.