Constraints on the sum of neutrino masses using cosmological data
  including the latest extended Baryon Oscillation Spectroscopic Survey DR14
  quasar sample
  We investigate the constraints on the sum of neutrino masses ($\Sigma m_\nu$)
using the most recent cosmological data, which combines the distance
measurement from baryonic acoustic oscillation in the extended Baryon
Oscillation Spectroscopic Survey DR14 quasar sample with the power spectra of
temperature and polarization anisotropies in the cosmic microwave background
from the Planck 2015 data release. We also use other low-redshift observations
including the baryonic acoustic oscillation at relatively low redshifts, the
supernovae of type Ia and the local measurement of Hubble constant. In the
standard cosmological constant $\Lambda$ cold dark matter plus massive neutrino
model, we obtain the $95\%$ \acl{CL} upper limit to be $\Sigma
m_\nu<0.129~\mathrm{eV}$ for the degenerate mass hierarchy, $\Sigma
m_{\nu}<0.159~\mathrm{eV}$ for the normal mass hierarchy, and $\Sigma
m_{\nu}<0.189~\mathrm{eV}$ for the inverted mass hierarchy. Based on Bayesian
evidence, we find that the degenerate hierarchy is positively supported, and
the current data combination can not distinguish normal and inverted
hierarchies. Assuming the degenerate mass hierarchy, we extend our study to
non-standard cosmological models including the generic dark energy, the spatial
curvature, and the extra relativistic degrees of freedom, respectively, but
find these models not favored by the data.
