# Cosmology and the neutrino mass ordering

## Abstract

We propose a simple method to quantify a possible exclusion of the inverted neutrino mass ordering from cosmological bounds on the sum of the neutrino masses. The method is based on Bayesian inference and allows for a calculation of the posterior odds of normal versus inverted ordering. We apply the method for a specific set of current data from Planck CMB data and large-scale structure surveys, providing an upper bound on the sum of neutrino masses of 0.14 eV at 95% CL. With this analysis we obtain posterior odds for normal versus inverted ordering of about 2:1. If cosmological data is combined with data from oscillation experiments the odds reduce to about 3:2. For an exclusion of the inverted ordering from cosmology at more than 95% CL, an accuracy of better than 0.02 eV is needed for the sum. We demonstrate that such a value could be reached with planned observations of large scale structure by analysing artificial mock data for a EUCLID-like survey.

- Authors:

- Department of Physics and Astronomy, Aarhus University, Ny Munkegade, DK-8000 Aarhus C (Denmark)
- Institut für Kernphysik, Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe (Germany)

- Publication Date:

- OSTI Identifier:
- 22679397

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2016; Journal Issue: 11; Other Information: Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; COSMOLOGY; MASS; NEUTRINOS; OSCILLATIONS; RELICT RADIATION

### Citation Formats

```
Hannestad, Steen, and Schwetz, Thomas, E-mail: sth@phys.au.dk, E-mail: schwetz@kit.edu.
```*Cosmology and the neutrino mass ordering*. United States: N. p., 2016.
Web. doi:10.1088/1475-7516/2016/11/035.

```
Hannestad, Steen, & Schwetz, Thomas, E-mail: sth@phys.au.dk, E-mail: schwetz@kit.edu.
```*Cosmology and the neutrino mass ordering*. United States. doi:10.1088/1475-7516/2016/11/035.

```
Hannestad, Steen, and Schwetz, Thomas, E-mail: sth@phys.au.dk, E-mail: schwetz@kit.edu. Tue .
"Cosmology and the neutrino mass ordering". United States. doi:10.1088/1475-7516/2016/11/035.
```

```
@article{osti_22679397,
```

title = {Cosmology and the neutrino mass ordering},

author = {Hannestad, Steen and Schwetz, Thomas, E-mail: sth@phys.au.dk, E-mail: schwetz@kit.edu},

abstractNote = {We propose a simple method to quantify a possible exclusion of the inverted neutrino mass ordering from cosmological bounds on the sum of the neutrino masses. The method is based on Bayesian inference and allows for a calculation of the posterior odds of normal versus inverted ordering. We apply the method for a specific set of current data from Planck CMB data and large-scale structure surveys, providing an upper bound on the sum of neutrino masses of 0.14 eV at 95% CL. With this analysis we obtain posterior odds for normal versus inverted ordering of about 2:1. If cosmological data is combined with data from oscillation experiments the odds reduce to about 3:2. For an exclusion of the inverted ordering from cosmology at more than 95% CL, an accuracy of better than 0.02 eV is needed for the sum. We demonstrate that such a value could be reached with planned observations of large scale structure by analysing artificial mock data for a EUCLID-like survey.},

doi = {10.1088/1475-7516/2016/11/035},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 11,

volume = 2016,

place = {United States},

year = {Tue Nov 01 00:00:00 EDT 2016},

month = {Tue Nov 01 00:00:00 EDT 2016}

}