A Cosmological Measurement of the Sum of the Neutrino masses with Precision CMB Observations

Abstract

This proceedings article presents a brief summary of the talk presented at the NOW2010 conference. I discussed the measurement of the sum of neutrino masses in cosmology. In particular, I suggested that the lensing of the cosmic microwave background (CMB) is a strong probe of the neutrino masses as the mass fluctuations responsible for lensing of the CMB are primarily at linear scales and at redshifts of 2 to 3. A first, direct measurement of the angular power spectrum of the projected lensing potential out to the last scattering surface has been achieved with WMAP 7-year cosmological data leading to the amplitude of the mass fluctuations to be 0.97 ± 0.47 in the flat-LCDM cosmological model. Efficient algorithms to extract the lensing signal in the CMB is now available from the literature. In future, all-sky 5 to 10 arcminute scale CMB experiments have the highest potential to extract the neutrino masses. With Planck, the sum of the neutrino masses can be constrained down to 0.15 eV, while with an experiment such as EPIC, this can be improved to 0.047 eV at the 95% confidence level. At such a sensitivity level, a measurement of the sum of the neutrino mass should be feasible given the existing oscillation experiments that suggest a mass sum at or above this level in both inverted and normal mass hierachies.