Determining neutrino properties using future galaxy redshift surveys

Abstract

Current measurements of the large-scale structure (LSS) of galaxies are able to place an ∼0.5 eV upper limit on the absolute mass scale of neutrinos. An order-of-magnitude improvement in raw sensitivity, together with an insensitivity to systematic effects, is needed to reach the lowest value allowed by particle physics experiments. We consider the prospects of determining both the neutrino mass scale and the number of massive neutrinos using future redshift surveys, specifically those undertaken with the Square Kilometre Array (SKA), with and without additional constraints from the upcoming Planck cosmic microwave background (CMB) experiment. If the sum of the neutrino masses then the imprint of neutrinos on LSS should be enough, on its own, to establish the neutrino mass scale and, considered alongside CMB constraints, it will also determine the number of massive neutrinos Nν, and hence the mass hierarchy. If ∑ mi ∼ 0.05 eV, at the bottom end of the allowed range, then a combination of LSS, CMB and particle physics constraints should be able to determine and the hierarchy. If is in the specific range 0.1- 0.25 eV, then a combination of LSS, CMB and particle physics experiments should determine, but not Nν or the hierarchy. Once an SKA-like LSS survey is available there are good prospects of obtaining a full understanding of the conventional neutrino sector, and a chance of finding evidence for sterile neutrinos. © 2007 The Authors. Journal compilation © 2007 RAS.