## 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 $\mathrm{\Lambda}\mathrm{CDM}$

## Abstract

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) = w _{0} + w _{a}z/(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 w _{0}, 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 w _{0} - w _{a} such that w (z) ≥ -1, allmore »

- Authors:

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

- Publication Date:

- Research Org.:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)

- Sponsoring Org.:
- USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)

- OSTI Identifier:
- 1544197

- Alternate Identifier(s):
- OSTI ID: 1475089

- Grant/Contract Number:
- SC0007859; 638-2013-8993; FPA2014–57816-P; SEV-2014-0398; 690575; 674896

- Resource Type:
- Accepted Manuscript

- Journal Name:
- Physical Review D

- Additional Journal Information:
- Journal Volume: 98; Journal Issue: 8; Journal ID: ISSN 2470-0010

- Publisher:
- American Physical Society (APS)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTRONOMY AND ASTROPHYSICS

### Citation Formats

```
Vagnozzi, Sunny, Dhawan, Suhail, Gerbino, Martina, Freese, Katherine, Goobar, Ariel, and Mena, Olga. Constraints on the sum of the neutrino masses in dynamical dark energy models with w(z)≥-1 are tighter than those obtained in ΛCDM. United States: N. p., 2018.
Web. doi:10.1103/PhysRevD.98.083501.
```

```
Vagnozzi, Sunny, Dhawan, Suhail, Gerbino, Martina, Freese, Katherine, Goobar, Ariel, & Mena, Olga. Constraints on the sum of the neutrino masses in dynamical dark energy models with w(z)≥-1 are tighter than those obtained in ΛCDM. United States. doi:10.1103/PhysRevD.98.083501.
```

```
Vagnozzi, Sunny, Dhawan, Suhail, Gerbino, Martina, Freese, Katherine, Goobar, Ariel, and Mena, Olga. Mon .
"Constraints on the sum of the neutrino masses in dynamical dark energy models with w(z)≥-1 are tighter than those obtained in ΛCDM". United States. doi:10.1103/PhysRevD.98.083501. https://www.osti.gov/servlets/purl/1544197.
```

```
@article{osti_1544197,
```

title = {Constraints on the sum of the neutrino masses in dynamical dark energy models with w(z)≥-1 are tighter than those obtained in ΛCDM},

author = {Vagnozzi, Sunny and Dhawan, Suhail and Gerbino, Martina and Freese, Katherine and Goobar, Ariel and Mena, Olga},

abstractNote = {In this work, we explore cosmological constraints on the sum of the three active neutrino masses Mν 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 + waz/(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 Mν 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, wa such that w(z) ≥ - 1 (but not w = -1 for all z), the upper limit on Mν is tighter than the Λ CDM limit because of the well-known degeneracy between w and Mν. The Bayesian analysis we have carried out then integrates over the possible values of w0 - wa such that w (z) ≥ -1, all of which correspond to tighter limits on Mν than the Λ CDM limit. We find a 95% credible interval (C.I.) upper bound of Mν < 0.13 eV . This bound can be compared with the 95% C.I. upper bounds of Mν < 0.16 eV , obtained within the Λ CDM model, and Mν < 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.},

doi = {10.1103/PhysRevD.98.083501},

journal = {Physical Review D},

number = 8,

volume = 98,

place = {United States},

year = {2018},

month = {10}

}

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