Special Universe Talk: Massive neutrinos and the tension between Large Scale Structure and the Cosmic Microwave Background

by Richard Battye (U Manchester)

Wednesday 12 Mar 2014, 16:30 → 17:30 Europe/Berlin

seminar room, basement (Excellence Cluster Universe)

There appear to be tensions between published measurements of the amplitude of density fluctuations on large scale made by the CMB temperature anisotropies and on smaller scales by large-scale structure probes. These include cluster counts, weak gravitational lensing (both of the CMB and galaxies) and redshift space distortions. We discuss this tension and the possible explanations. These include incorrect interpretation of the observations and the possible addition of new physics to the standard model of cosmology. In particular we calculate the neutrino masses (both for active and sterile species) that would be need to resolve the discrepancy. Prime facie there is a preference of around 4 standard deviations for non-zero neutrino masses.