Constraints on the sum of the neutrino masses in dynamical dark energy models with $w\left(z\right)\ge -1$ are tighter than those obtained in $\mathrm{\Lambda }\mathrm{CDM}$

Journal Article · 01 October 2018 · Physical Review D

DOI: https://doi.org/10.1103/PhysRevD.98.083501 · OSTI ID:1544197

Vagnozzi, Sunny ^[1]; Dhawan, Suhail ^[2]; Gerbino, Martina ^[2]; Freese, Katherine ^[3]; Goobar, Ariel ^[2]; Mena, Olga ^[4]

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1. Stockholm Univ. (Sweden); The Nordic Institute for Theoretical Physics (NORDITA), Stockholm (Sweden)
2. Stockholm Univ. (Sweden)
3. Stockholm Univ. (Sweden); The Nordic Institute for Theoretical Physics (NORDITA), Stockholm (Sweden); Univ. of Michigan, Ann Arbor, MI (United States)
4. Universidad de Valencia-CSIC, Valencia (Spain)

In this work, we explore cosmological constraints on the sum of the three active neutrino masses M_ν in the context of dynamical dark energy (DDE) models with equation of state (EoS) parametrized as a function of redshift z by w(z) = w₀ + w_az/(1 + z), and satisfying w(z) ≥ -1 for all z. We make use of cosmic microwave background data from the Planck satellite, baryon acoustic oscillation measurements, and supernovae Ia luminosity distance measurements, and perform a Bayesian analysis. We show that, within these models, the bounds on M_ν do not degrade with respect to those obtained in the Λ CDM case; in fact, the bounds are slightly tighter, despite the enlarged parameter space. We explain our results based on the observation that, for fixed choices of w₀, w_a such that w(z) ≥ - 1 (but not w = -1 for all z), the upper limit on M_ν is tighter than the Λ CDM limit because of the well-known degeneracy between w and M_ν. The Bayesian analysis we have carried out then integrates over the possible values of w₀ - w_a such that w (z) ≥ -1, all of which correspond to tighter limits on M_ν than the Λ CDM limit. We find a 95% credible interval (C.I.) upper bound of M_ν < 0.13 eV . This bound can be compared with the 95% C.I. upper bounds of M_ν < 0.16 eV , obtained within the Λ CDM model, and M_ν < 0.41 eV, obtained in a DDE model with arbitrary EoS (which allows values of w < -1). Contrary to the results derived for DDE models with arbitrary EoS, we find that a dark energy component with w(z) ≥ -1 is unable to alleviate the tension between high-redshift observables and direct measurements of the Hubble constant H₀. Lastly, in light of the results of this analysis, we also discuss the implications for DDE models of a possible determination of the neutrino mass ordering by laboratory searches.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Univ. of Michigan, Ann Arbor, MI (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: SC0007859
• OSTI ID: 1544197
• Journal Information: Physical Review D, Journal Name: Physical Review D Journal Issue: 8 Vol. 98; ISSN PRVDAQ; ISSN 2470-0010
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English