Impacts of dark energy on weighing neutrinos: mass hierarchies considered

Sai Wang, Yi-Fan Wang, Dong-Mei Xia, Xin Zhang

Published 2016-08-02Version 1

Taking into account the mass splittings between three active neutrinos, we investigate potential impacts of dark energy on constraining the total neutrino mass $\sum m_{\nu}$ by using recent cosmological observations. We consider two typical dark energy models, namely, the $w$CDM model and the holographic dark energy (HDE) model, which both have an additional parameter than the $\Lambda$CDM model. We employ the Planck 2015 data of CMB temperature and polarization anisotropies, combined with low-redshift measurements on BAO distance scales, type Ia supernovae, Hubble constant, and Planck lensing. Comparing with the $\Lambda$CDM model, our studies show that the upper limit on $\sum m_{\nu}$ becomes much looser in the $w$CDM model while much tighter in the HDE model. In the HDE model, we obtain the $95\%$ CL upper limit $\sum m_{\nu}<0.105~\textrm{eV}$ for three degenerate neutrinos. This might be the most stringent constraint on $\sum m_{\nu}$ by far. Even though the minimal $\chi^2$ is slightly smaller for the normal hierarchy than that for the inverted hierarchy, the difference $\Delta \chi^2$ is still not significant enough to distinguish the neutrino mass hierarchies.