Neutrino clustering in growing neutrino quintessence

A growing neutrino mass can stop the dynamical evolution of a dark energy scalar field, thus explaining the 'why now' problem. We show that such models lead to a substantial neutrino clustering on the scales of superclusters. Nonlinear neutrino lumps form at redshift z \sim 1 and could partially drag the clustering of dark matter. If observed, large scale non-linear structures could be an indication for a new attractive 'cosmon force' stronger than gravity.Comment: 6 pages, 5 figure

Equilibrium and stability of neutrino lumps as TOV solutions

We report about stability conditions for static, spherically symmetric objects that share the essential features of mass varying neutrinos in cosmological scenarios. Compact structures of particles with variable mass are held together preponderantly by an attractive force mediated by a background scalar field. Their corresponding conditions for equilibrium and stability are given in terms of the ratio between the total mass-energy and the spherical lump radius, $M/R$. We show that the mass varying mechanism leading to lump formation can modify the cosmological predictions for the cosmological neutrino mass limits. Our study comprises Tolman-Oppenheimer-Volkoff solutions of relativistic objects with non-uniform energy densities. The results leave open some questions concerning stable regular solutions that, to an external observer, very closely reproduce the preliminary conditions to form Schwarzschild black holes.Comment: 20 pages, 5 figure

First neutrino observations from the sudbury neutrino observatory

The first neutrino observations from the Sudbury Neutrino Observatory are presented from preliminary analyses. Based on energy, direction and location, the data in the region of interest appear to be dominated by 8B solar neutrinos, detected by the charged current reaction on deuterium and elastic scattering from electrons, with very little background. Measurements of radioactive backgrounds indicate that the measurement of all active neutrino types via the neutral current reaction on deuterium will be possible with small systematic uncertainties. Quantitative results for the fluxes observed with these reactions will be provided when further calibrations have been completed