Giusarma, E., Corsi, M., Archidiacono, M., de Putter, R., Melchiorri, A., Mena, O., et al. (2011). Constraints on massive sterile neutrino species from current and future cosmological data. Phys. Rev. D, 83(11), 115023–10pp.
Abstract: Sterile massive neutrinos are a natural extension of the standard model of elementary particles. The energy density of the extra sterile massive states affects cosmological measurements in an analogous way to that of active neutrino species. We perform here an analysis of current cosmological data and derive bounds on the masses of the active and the sterile neutrino states, as well as on the number of sterile states. The so-called (3 + 2) models, with three sub-eV active massive neutrinos plus two sub-eV massive sterile species, is well within the 95% CL allowed regions when considering cosmological data only. If the two extra sterile states have thermal abundances at decoupling, big bang nucleosynthesis bounds compromise the viability of (3 + 2) models. Forecasts from future cosmological data on the active and sterile neutrino parameters are also presented. Independent measurements of the neutrino mass from tritium beta-decay experiments and of the Hubble constant could shed light on sub-eV massive sterile neutrino scenarios.
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De Bernardis, F., Martinelli, M., Melchiorri, A., Mena, O., & Cooray, A. (2011). Future weak lensing constraints in a dark coupled universe. Phys. Rev. D, 84(2), 023504–10pp.
Abstract: Probing the dark matter clustering and its evolution with weak lensing surveys constitutes a unique tool to constrain interacting dark energy models. We focus here on weak lensing forecasts from future Euclid and LSST-like surveys combined with the expected results from the ongoing Planck cosmic microwave background satellite experiment. We find that these future data could constrain the dimensionless coupling between dark matter and dark energy to be smaller than a few x 10(-2), improving the CMB-only constraint by at least 2 orders of magnitude. We also show that coupled cosmologies can substantially alter the constraints on cosmological parameters obtained from CMB experiments under the assumption of noninteracting cosmologies unless weak lensing data is considered.
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Lopez-Honorez, L., Mena, O., & Rigolin, S. (2012). Biases on cosmological parameters by general relativity effects. Phys. Rev. D, 85(2), 023511–12pp.
Abstract: General relativistic corrections to the galaxy power spectrum appearing at the horizon scale, if neglected, may induce biases on the measured values of the cosmological parameters. In this paper, we study the impact of general relativistic effects on non standard cosmologies such as scenarios with a time dependent dark energy equation of state, with a coupling between the dark energy and the dark matter fluids or with non-Gaussianities. We then explore whether general relativistic corrections affect future constraints on cosmological parameters in the case of a constant dark energy equation of state and of non-Gaussianities. We find that relativistic corrections on the power spectrum are not expected to affect the foreseen errors on the cosmological parameters nor to induce large biases on them.
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Martinelli, M., Melchiorri, A., Mena, O., Salvatelli, V., & Girones, Z. (2012). Future constraints on the Hu-Sawicki modified gravity scenario. Phys. Rev. D, 85(2), 024006–7pp.
Abstract: We present current and future constraints on the Hu and Sawicki modified gravity scenario. This model can reproduce a late time accelerated universe and evade Solar System constraints. While current cosmological data still allows for distinctive deviations from the cosmological constant picture, future measurements of the growth of structure combined with supernova Ia luminosity distance data will greatly improve present constraints.
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Giusarma, E., Archidiacono, M., de Putter, R., Melchiorri, A., & Mena, O. (2012). Sterile neutrino models and nonminimal cosmologies. Phys. Rev. D, 85(8), 083522–9pp.
Abstract: Cosmological measurements are affected by the energy density of massive neutrinos. We extend here a recent analysis of current cosmological data to nonminimal cosmologies. Several possible scenarios are examined: a constant w not equal -1 dark energy equation of state, a nonflat universe, a time-varying dark energy component and coupled dark matter-dark energy universes or modified gravity scenarios. When considering cosmological data only, (3 + 2) massive neutrino models with similar to 0.5 eV sterile species are allowed at 95% confidence level. This scenario has been shown to reconcile reactor, LSND and MiniBooNE positive signals with null results from other searches. Big bang nucleosynthesis bounds could compromise the viability of (3 + 2) models if the two sterile species are fully thermalized states at decoupling.
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