Neutrino mass from cosmology: impact of high-accuracy measurement of the Hubble constant

Non-zero neutrino mass would affect the evolution of the Universe in observable ways, and a strong constraint on the mass can be achieved using combinations of cosmological data sets. We focus on the power spectrum of cosmic microwave background (CMB) anisotropies, the Hubble constant H-0, and the length scale for baryon acoustic oscillations (BAO) to investigate the constraint on the neutrino mass, m(nu). We analyze data from multiple existing CMB studies (WMAP5, ACBAR, CBI, BOOMERANG, and QUAD), recent measurement of H-0 (SHOES), with about two times lower uncertainty (5%) than previous estimates, and recent treatments of BAO from the Sloan Digital Sky Survey (SDSS). We obtained an upper limit of m(nu) < 0.2 eV (95 % CL.), for a flat ACDM model. This is a 40% reduction in the limit derived from previous H-0 estimates and one-third lower than can be achieved with extant CMB and BAO data. We also analyze the impact of smaller uncertainty on measurements of H-0 as may be anticipated in the near term, in combination with CMB data from the Planck mission, and BAO data from the SDSS/BOSS program. We demonstrate the possibility of a 5 sigma detection for a fiducial neutrino films of 0.1 eV or a 95% upper limit of 0.04 eV for a fiducial of m(nu) = 0 eV. These constraints are about 50 % better than those achieved without external constraint. We further investigate the impact on modeling where the dark-energy equation of state is constant but not necessarily -1, or where a non-flat universe is allowed. In these cases, the next-generation accuracies of Planck, BOSS, and 1 % measurement of H-0 would all be required to obtain the limit m(nu) < 0.05 - 0.06 eV (95 % CL.) for the fiducial of m(nu) = 0 eV. The independence of systematics argues for pursuit of both BAO and H-0 measurements.