Date Published:

September 1, 201

Abstract:

We obtain constraints on cosmological parameters from the sphericallyaveraged redshift-space correlation function of the CMASS Data Release 9(DR9) sample of the Baryonic Oscillation Spectroscopic Survey (BOSS). Wecombine this information with additional data from recent cosmicmicrowave background (CMB), supernova and baryon acoustic oscillationmeasurements. Our results show no significant evidence of deviationsfrom the standard flat Λ cold dark matter model, whose basicparameters can be specified by Ω_m = 0.285 ±0.009, 100 Ω_b = 4.59 ± 0.09, n_s =0.961 ± 0.009, H₀ = 69.4 ± 0.8 kms^-1 Mpc^-1 and σ₈ = 0.80 ±0.02. The CMB+CMASS combination sets tight constraints on the curvatureof the Universe, with Ω_k = -0.0043 ± 0.0049, andthe tensor-to-scalar amplitude ratio, for which we find r < 0.16 atthe 95 per cent confidence level (CL). These data show a clear signatureof a deviation from scale invariance also in the presence of tensormodes, with n_s < 1 at the 99.7 per cent CL. We deriveconstraints on the fraction of massive neutrinos of f_ν< 0.049 (95 per cent CL), implying a limit of ∑m_ν< 0.51 eV. We find no signature of a deviation from a cosmologicalconstant from the combination of all data sets, with a constraint ofw_DE = -1.033 ± 0.073 when this parameter is assumedtime-independent, and no evidence of a departure from this value when itis allowed to evolve as w_DE(a) = w₀ +w_a(1 - a). The achieved accuracy on our cosmologicalconstraints is a clear demonstration of the constraining power ofcurrent cosmological observations.

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