Article

# The WiggleZ Dark Energy Survey: Cosmological neutrino mass constraint from blue high-redshift galaxies

12/2011; DOI:10.1103/PhysRevD.85.081101
Source: arXiv

ABSTRACT The absolute neutrino mass scale is currently unknown, but can be constrained
from cosmology. The WiggleZ high redshift star-forming blue galaxy sample is
less sensitive to systematics from non-linear structure formation,
redshift-space distortions and galaxy bias than previous surveys. We obtain a
upper limit on the sum of neutrino masses of 0.60eV (95% confidence) for
WiggleZ+Wilkinson Microwave Anisotropy Probe. Combining with priors on the
Hubble Parameter and the baryon acoustic oscillation scale gives an upper limit
of 0.29eV, which is the strongest neutrino mass constraint derived from
spectroscopic galaxy redshift surveys.

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##### Article: Simplest Neutrino Mixing from S4 Symmetry
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ABSTRACT: In 2004, two of us proposed a texture, the "Simplest" neutrino mass matrix, which predicted sin(theta13)=sqrt((2 Solar-Delta m^2)/(3 Atm-Delta m^2)) and delta_CP=90 degrees. Using today's measured values for neutrino mass-squared differences, this prediction gives sin^2(theta13)~0.086+0.003-0.006, compared with a measured value, found by averaging the results of the Daya Bay and RENO experiments, of sin^2(theta13)=0.093+0.010-0.010. Here we present a specific model based on S4 symmetry leading to this successful texture in the context of the type-1 see-saw mechanism, assuming Majorana neutrinos. In this case, slightly different predictions are obtained relating theta13 to the light neutrino masses, which are in accord with current experimental limits and testable at future experiments. Large CP asymmetries remain a generic prediction of the texture.
Journal of High Energy Physics 11/2012; 2013(4). · 5.62 Impact Factor
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##### Article: Cosmology with massive neutrinos I: towards a realistic modeling of the relation between matter, haloes and galaxies
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ABSTRACT: By using a suite of large box-size N-body simulations that incorporate massive neutrinos as an extra set of particles, we investigate the impact of neutrino masses on the spatial distribution of dark matter haloes and galaxies. We compute the bias between the spatial distribution of dark matter haloes and the overall matter and cold dark matter distributions using statistical tools such as the power spectrum and the two-point correlation function. Overall we find a scale-dependent bias on large scales for the cosmologies with massive neutrinos. However, our results indicate that the scale-dependence in the bias is reduced if the latter is computed with respect to the cold dark matter distribution only. We find that the value of the bias on large scales is reasonably well reproduced by the Tinker fitting formula once the linear cold dark matter power spectrum is used, instead of the total matter power spectrum. We investigate whether scale-dependent bias really comes from purely neutrino's effect or from nonlinear gravitational collapse of haloes. For this purpose, we address the $\Omega_\nu$-$\sigma_8$ degeneracy and find that such degeneracy is not perfect, implying that neutrinos imprint a slight scale dependence on the large-scale bias. Finally, by using a simple halo occupation distribution (HOD) model, we investigate the impact of massive neutrinos on the distribution of galaxies within dark matter haloes. We use the main galaxy sample in the Sloan Digital Sky Survey II Data Release 7 to investigate if the small-scale galaxy clustering alone can be used to discriminate among different cosmological models with different neutrino masses. Our results suggest that different choices of the HOD parameters can reproduce the observational measurements relatively well, and we quantify the difference between the values of the HOD parameters between massless and massive neutrino cosmologies.
11/2013;