scholarly journals MEASURING NEUTRINO MASSES AND DARK ENERGY

2008 ◽  
Vol 23 (34) ◽  
pp. 2881-2895
Author(s):  
HUITZU TU
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Neutrino Mass ◽  
Energy Equation ◽  
Mass Scale ◽  
Neutrino Masses ◽  
Acoustic Oscillations ◽  
Distance Measurements ◽  
The Galaxy ◽  
Absolute Neutrino Mass

We review some recent efforts in determining the absolute neutrino mass scale in cosmology. We illustrate in particular how distance measurements such as the baryon acoustic oscillations and the galaxy weak lensing can break the degeneracy between the neutrino mass and dark energy equation of state parameters.

scholarly journals The SO(10)-inspired leptogenesis timely opportunity

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Pasquale Di Bari ◽  
Rome Samanta
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Lower Bounds ◽  
Neutrinoless Double Beta Decay ◽  
Mass Scale ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Neutrino Mixing ◽  
Mixing Parameters ◽  
Absolute Neutrino Mass

Abstract We study the connection between absolute neutrino mass and neutrino mixing parameters within SO(10)-inspired leptogenesis. We show that current favoured values of the unknown neutrino mixing parameters point toward values of the absolute neutrino mass scale that will be fully tested by cosmological observations and neutrinoless double beta decay experiments during next years. In particular, for mD2/mcharm≤ 5, where mD2 is the intermediate Dirac neutrino mass, and for current best fit values of the Dirac phase δ and the atmospheric mixing angle θ23, we derive a lower bound on the neutrinoless double beta decay effective neutrino mass mee ≳ 31 meV and on the sum of the neutrino masses Σimi ≳ 125 meV. These lower bounds hold for normally ordered neutrino masses, as currently favoured by global analyses, and approximately for δ ∈ [155°, 240°] and θ23 in the second octant. If values in this region will be confirmed by future planned long baseline experiments, then a signal at next generation neutrinoless double beta decay experiments is expected, despite neutrino masses being normally ordered. Outside the region, the lower bounds strongly relax but a great fraction of the allowed range of values still allows a measurement of the lightest neutrino mass. Therefore, in the next years low energy neutrino experiments will provide a stringent test of SO(10)-inspired leptogenesis, that might result either in severe constraints or in a strong evidence.

scholarly journals Non-linear interacting cosmological models after Planck 2018 legacy release and the H0 tension

2020 ◽  
Vol 493 (3) ◽  
pp. 3114-3131 ◽  
Author(s):  
Supriya Pan ◽  
Weiqiang Yang ◽  
Andronikos Paliathanasis
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Observational Data ◽  
Energy Equation ◽  
Hubble Space Telescope ◽  
Hubble Constant ◽  
Acoustic Oscillations ◽  
Coincidence Problem ◽  
Linear Interaction ◽  
Non Linear

ABSTRACT Interacting dark energy models are widely renowned for giving an explanation to the cosmic coincidence problem as well as several observational issues. According to the recent observational data, and so far we are concerned with the literature, the choice of the interaction function between dark matter and dark energy is always questionable since there is no such underlying theory that could derive it. Thus, in this work we have raised this issue by proposing two new non-linear interaction functions and constrain them using cosmic microwave background (CMB) from Planck 2018, baryon acoustic oscillations (BAOs), dark energy survey and a measurement of the Hubble constant H0 from Hubble Space Telescope (HST) 2019. The dark energy equation of state is considered to be constant throughout the work and the geometry of the universe is assumed to be homogeneous and isotropic with zero spatial curvature. Our analyses report that a non-zero interaction is always allowed by the observational data and the dark energy equation of state is bent towards the phantom regime. In particular, when H0 from HST is added to Planck 2018+BAO, we find an evidence for a non-zero coupling at more than 2σ confidence level. Our analyses also report that for both the models, H0 is close to its local measurements and thus alleviating the H0 tension. In particular, one of the interacting models perfectly solves the H0 tension.

scholarly journals Leptonic sum rules from flavour models with modular symmetries

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
J. Gehrlein ◽  
M. Spinrath
Keyword(s):  
Neutrino Mass ◽  
Sum Rules ◽  
Mass Scale ◽  
Neutrino Masses ◽  
Mixing Angles ◽  
Mixing Parameters ◽  
Neutrino Experiments ◽  
Parameter Ranges ◽  
Absolute Neutrino Mass ◽  
Analytical Expressions

Abstract Sum rules in the lepton sector provide an extremely valuable tool to classify flavour models in terms of relations between neutrino masses and mixing parameters testable in a plethora of experiments. In this manuscript we identify new leptonic sum rules arising in models with modular symmetries with residual symmetries. These models simultaneously present neutrino mass sum rules, involving masses and Majorana phases, and mixing sum rules, connecting the mixing angles and the Dirac CP-violating phase. The simultaneous appearance of both types of sum rules leads to some non-trivial interplay, for instance, the allowed absolute neutrino mass scale exhibits a dependence on the Dirac CP-violating phase. We derive analytical expressions for these novel sum rules and present their allowed parameter ranges as well as their predictions at upcoming neutrino experiments.

scholarly journals Observational Constraints on Dynamical Dark Energy with Pivoting Redshift

Universe ◽  
2019 ◽  
Vol 5 (11) ◽  
pp. 219 ◽  
Author(s):  
Weiqiang Yang ◽  
Supriya Pan ◽  
Eleonora Di Valentino ◽  
Emmanuel N. Saridakis
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Free Parameter ◽  
Energy Equation ◽  
Hubble Constant ◽  
Mean Value ◽  
Observational Constraints ◽  
Acoustic Oscillations ◽  
Light Curve Analysis ◽  
Full Data

We investigate the generalized Chevallier–Polarski–Linder (CPL) parametrization, which contains the pivoting redshift z p as an extra free parameter, in order to examine whether the evolution of the dark energy equation of state can be better described by a different parametrization. We use various data combinations from cosmic microwave background (CMB), baryon acoustic oscillations (BAO), redshift space distortion (RSD), weak lensing (WL), joint light curve analysis (JLA), and cosmic chronometers (CC), and we include a Gaussian prior on the Hubble constant value, in order to extract the observational constraints on various quantities. For the case of free z p we find that for all data combinations it always remains unconstrained, and there is a degeneracy with the value of the dark energy equation of state w 0 p at z p . For the case where z p is fixed to specific values, and for the full data combination, we find that with increasing z p the mean value of w 0 p slowly moves into the phantom regime, however the cosmological constant is always allowed within 1 σ confidence-level. In fact, the significant effect is that with increasing z p , the correlations between w 0 p and w a (the free parameter of the dark energy equation of state quantifying its evolution with redshift), change from negative to positive, with the case z p = 0 . 35 corresponding to no correlation. The fact that the two parameters describing the dark energy equation of state are uncorrelated for z p = 0 . 35 justifies why a non-zero pivoting redshift needs to be taken into account.

scholarly journals Cosmological Surveys with the Australian Square Kilometre Array Pathfinder

2012 ◽  
Vol 29 (2) ◽  
pp. 202-211 ◽  
Author(s):  
A. R. Duffy ◽  
A. Moss ◽  
L. Staveley-Smith
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Power Spectrum ◽  
Energy Equation ◽  
Coming Of Age ◽  
Neutral Hydrogen ◽  
Square Kilometre Array ◽  
Cosmological Constraints ◽  
Sky Survey ◽  
The Galaxy

AbstractThis is a design study into the capabilities of the Australian Square Kilometre Array Pathfinder in performing a full-sky low redshift neutral hydrogen survey, termed WALLABY, and the potential cosmological constraints one can attain from measurement of the galaxy power spectrum. We find that the full sky survey will likely attain 6 × 105 redshifts which, when combined with expected Planck CMB data, will constrain the Dark Energy equation of state to 20%, representing a coming of age for radio observations in creating cosmological constraints.

scholarly journals Nonparametric reconstruction of the dark energy equation of state from diverse data sets

2011 ◽  
Vol 84 (8) ◽  
Author(s):  
Tracy Holsclaw ◽  
Ujjaini Alam ◽  
Bruno Sansó ◽  
Herbie Lee ◽  
Katrin Heitmann ◽  
...  
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Energy Equation ◽  
Data Sets ◽  
Diverse Data
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