Search results for "CMB"
showing 10 items of 30 documents
Observables sensitive to absolute neutrino masses. II
2008
In this followup to Phys. Rev. D 75, 053001 (2007) [arXiv:hep-ph/0608060] we report updated constraints on neutrino mass-mixing parameters, in light of recent neutrino oscillation data (KamLAND, SNO, and MINOS) and cosmological observations (WMAP 5-year and other data). We discuss their interplay with the final 0nu2beta decay results in 76-Ge claimed by part of the Heidelberg-Moscow Collaboration, using recent evaluations of the corresponding nuclear matrix elements, and their uncertainties. We also comment on the 0nu2beta limits in 130-Te recently set by Cuoricino, and on prospective limits or signals from the KATRIN experiment.
Sachs-Wolfe at second order: the CMB bispectrum on large angular scales
2009
We calculate the Cosmic Microwave Background anisotropy bispectrum on large angular scales in the absence of primordial non-Gaussianities, assuming exact matter dominance and extending at second order the classic Sachs-Wolfe result delta T/T = Phi/3. The calculation is done in Poisson gauge. Besides intrinsic contributions calculated at last scattering, one must consider integrated effects. These are associated to lensing, and to the time dependence of the potentials (Rees-Sciama) and of the vector and tensor components of the metric generated at second order. The bispectrum is explicitly computed in the flat-sky approximation. It scales as l(-4) in the scale invariant limit and the shape d…
Cosmology in a certain vector-tensor theory of gravitation
2014
We study relevant cosmological topics in the framework of a certain vector-tensor theory of gravitation (hereafter VT). This theory is first compared with the so-called extended electromagnetism (EE). These theories have a notable resemblance and both explain the existence of a cosmological constant. It is shown that, in EE, a positive dark energy density requires a Lagrangian leading to quantum ghosts, whereas VT is free from these ghosts. On account of this fact, the remainder of the paper is devoted to study cosmology in the framework of VT. Initial conditions, at high redshift, are used to solve the evolution equations of all the VT scalar modes. In particular, a certain scalar mode cha…
Current cosmological bounds on neutrino masses and relativistic relics
2004
We combine the most recent observations of large-scale structure (2dF and SDSS galaxy surveys) and cosmic microwave anisotropies (WMAP and ACBAR) to put constraints on flat cosmological models where the number of massive neutrinos and of massless relativistic relics are both left arbitrary. We discuss the impact of each dataset and of various priors on our bounds. For the standard case of three thermalized neutrinos, we find an upper bound on the total neutrino mass sum m_nu < 1.0 (resp. 0.6) eV (at 2sigma), using only CMB and LSS data (resp. including priors from supernovae data and the HST Key Project), a bound that is quite insensitive to the splitting of the total mass between the th…
Measuring the cosmological background of relativistic with the Wilkinson Microwave Anisotropy Probe
2003
We show that the first year results of the Wilkinson Microwave Anisotropy Probe (WMAP) constrain very efficiently the energy density in relativistic particles in the Universe. We derive new bounds on additional relativistic degrees of freedom expressed in terms of an excess in the effective number of light neutrinos $\ensuremath{\Delta}{N}_{\mathrm{eff}}.$ Within the flat \ensuremath{\Lambda}CDM scenario, the allowed range is $\ensuremath{\Delta}{N}_{\mathrm{eff}}l6$ (95% confidence level) using WMAP data only, or $\ensuremath{-}2.6l\ensuremath{\Delta}{N}_{\mathrm{eff}}l4$ with the prior ${H}_{0}=72\ifmmode\pm\else\textpm\fi{}8\mathrm{km}{\mathrm{s}}^{\ensuremath{-}1}{\mathrm{Mpc}}^{\ensure…
Model-independent fit to Planck and BICEP2 data
2014
Inflation is the leading theory to describe elegantly the initial conditions that led to structure formation in our universe. In this paper, we present a novel phenomenological fit to the Planck, WMAP polarisation (WP) and the BICEP2 datasets using an alternative parameterisation. Instead of starting from inflationary potentials and computing the inflationary observables, we use a phenomenological parameterisation due to Mukhanov, describing inflation by an effective equation-of-state, in terms of the number of e-folds and two phenomenological parameters $\alpha$ and $\beta$. Within such a parametrisation, which captures the different inflationary models in a model-independent way, the valu…
Cosmological Applications of Extended Electromagnetism
2013
Extended electromagnetism (EE) has been applied to cosmology in various papers. In all of them, the zero order energy density of the EE vector field plays the same role as vacuum energy. Perturbations of this field have been studied by using different approaches. Firstly, some basic equations and ideas are summarized and, then, the CMBFAST code is used to calculate the cosmic microwave background angular power spectrum for appropriate values of the EE parameters. Comparisons of the resulting spectra with a good observational one compatible with WMAP7 (Wilkinson map anisotropy probe 7 years data) seem to be promising. We are currently looking for a set of parameters leading to the best fitti…
Neutrino Mass Ordering from Oscillations and Beyond: 2018 Status and Future Prospects
2018
The ordering of the neutrino masses is a crucial input for a deep understanding of flavor physics, and its determination may provide the key to establish the relationship among the lepton masses and mixings and their analogous properties in the quark sector. The extraction of the neutrino mass ordering is a data-driven field expected to evolve very rapidly in the next decade. In this review, we both analyze the present status and describe the physics of subsequent prospects. Firstly, the different current available tools to measure the neutrino mass ordering are described. Namely, reactor, long-baseline (accelerator and atmospheric) neutrino beams, laboratory searches for beta and neutrinol…
Cosmic microwave background constraints on secret interactions among sterile neutrinos
2017
Secret contact interactions among eV sterile neutrinos, mediated by a massive gauge boson $X$ (with $M_X \ll M_W$), and characterized by a gauge coupling $g_X$, have been proposed as a mean to reconcile cosmological observations and short-baseline laboratory anomalies. We constrain this scenario using the latest Planck data on Cosmic Microwave Background anisotropies, and measurements of baryon acoustic oscillations (BAO). We consistently include the effect of secret interactions on cosmological perturbations, namely the increased density and pressure fluctuations in the neutrino fluid, and still find a severe tension between the secret interaction framework and cosmology. In fact, taking i…
Análisis de la problemática del pie diabético en la Comunidad Valenciana (2009-2013)
2016
Introducción: Las úlceras son la principal causa de hospitalización en el paciente diabético y motivo de complicaciones, como la amputación de miembro inferior. Objetivos: Conocer y analizar los ingresos de pacientes diabéticos con úlcera en el pie en los hospitales públicos de la Comunidad Valenciana durante el periodo 2009-2013, según bases de datos hospitalarios. Calcular las estancias, tasas y costes de dichos ingresos. Determinar la relación entre ingresos y el registro de podólogos ejercientes colegiados. Conocer la formación, prevención y recursos materiales que existen en los centros de atención primaria de la ciudad de Valencia en relación con la úlcera de pie diabético. Material y…