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Recent cosmological analyses based on DESI and CMB data have revealed a tension between the inferred sum of neutrino masses and the minimum value allowed by neutrino oscillation experiments, when assuming an underlying $\Lambda$CDM model of…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-21 Cihad Kıbrıs , Willem Elbers , Özgür Akarsu , Eleonora Di Valentino

Distance-redshift data can impose strong constraints on dark energy models even when the equation of state is oscillatory. Despite the double integral dependence of the distance on the equation of state, precision measurement of the…

Astrophysics · Physics 2009-11-13 Eric V. Linder

In this letter we argue that the CPL parameterisation for the dark energy equation of state is biased towards preferring such model over the constant $w$ while the latter bounds are still compatible with LCDM. For that we compare…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-27 Ziad Sakr

In this work, two completely different approaches, statefinder with error bars and Bayesian evidence, are used to distinguish and judge three time-dependent dark energy models. The parameters constrain for the three dark energy models are…

General Relativity and Quantum Cosmology · Physics 2016-10-14 Hongchao Zhang , Enkun Li , Lixin Xu

Models of dark energy are conveniently characterized by the equation-of-state parameter w=p/\rho, where \rho is the energy density and p is the pressure. Imposing the Dominant Energy Condition, which guarantees stability of the theory,…

Astrophysics · Physics 2011-05-12 Sean M. Carroll , Mark Hoffman , Mark Trodden

We study constraints from the latest CMB, large scale structure (2dF, Abell/ACO, PSCz) and SN1a data on dark energy models with a sharp transition in their equation of state, w(z). Such a transition is motivated by models like vacuum…

Astrophysics · Physics 2009-11-07 Bruce A. Bassett , Martin Kunz , Joseph Silk , Carlo Ungarelli

Cosmological constraints on a time-varying dark energy equation of state are fundamentally limited by the integral structure through which the equation of state enters cosmological observables. We rigorously derive the linear response…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-13 Seokcheon Lee

Baryon acoustic oscillation data from the Dark Energy Spectroscopic Instrument (DESI) show evidence of a deviation from a cosmological constant $\Lambda$ within a Bayesian analysis. In this work, we validate that frequentist constraints…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-16 Laura Herold , Tanvi Karwal

Using the general connection between the upper limit on the neutrino mass and the upper limits on certain types of non-Standard Model interaction that can generate loop corrections to the neutrino mass, we derive constraints on some…

High Energy Physics - Phenomenology · Physics 2007-05-23 Takeyasu M. Ito , Gary Prezeau

In our work on the development of model-independent data analysis methods for determining ratios between different couplings/cross sections of Weakly Interacting Massive Particles (WIMPs) by using measured recoil energies from direct Dark…

High Energy Physics - Phenomenology · Physics 2011-08-17 Chung-Lin Shan

The main aim of this work is to use a model-independent approach, along with late-time observational probes, to reconstruct the dark energy (DE) equation of state $w_{\rm DE}(z)$. Our analysis showed that, for a late time universe, $w_{\rm…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-23 Luis A. Escamilla , Supriya Pan , Eleonora Di Valentino , Andronikos Paliathanasis , J. Alberto Vázquez , Weiqiang Yang

We constrain two dynamical dark energy models that are parametrized by the logarithm form of $w(z)=w_{0}+w_{1}\left(\frac{\ln (2+z)}{1+z}-\ln 2\right)$ and the oscillating form of…

General Relativity and Quantum Cosmology · Physics 2023-11-28 Tian-Ying Yao , Rui-Yun Guo , Xin-Yue Zhao

Spin-dependent WIMP searches have traditionally presented results within an odd group approximation and by suppressing one of the spin-dependent interaction cross sections. We here elaborate on a model-independent analysis in which…

High Energy Physics - Phenomenology · Physics 2008-11-26 F. Giuliani , TA Girard

The variation of dark energy density with redshift, $\rho_X(z)$, provides a critical clue to the nature of dark energy. Since $\rho_X(z)$ depends on the dark energy equation of state $w_X(z)$ through an integral, $\rho_X(z)$ can be…

Astrophysics · Physics 2009-11-10 Yun Wang , Katherine Freese

If the dark energy density asymptotically approaches a nonzero constant, $\rho_{DE} \rightarrow \rho_0$, then its equation of state parameter $w$ necessarily approaches $-1$. The converse is not true; dark energy with $w \rightarrow -1$ can…

General Relativity and Quantum Cosmology · Physics 2018-06-20 Robert J. Scherrer

We present constraints on the dark energy equation-of-state parameter, w=P/(rho c^2), using 60 Type Ia supernovae (SNe Ia) from the ESSENCE supernova survey. We derive a set of constraints on the nature of the dark energy assuming a flat…

We present updated constraints on cosmological parameters in a 12-parameter model, extending the standard six-parameter $\Lambda$CDM by including dynamical dark energy (DE: $w_0$, $w_a$), the sum of neutrino masses ($\sum m_{\nu}$), the…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-19 Shouvik Roy Choudhury , Teppei Okumura

The time dependence of the dark energy density can be an important clue to the nature of dark energy in the universe. We show that future supernova data from dedicated telescopes (such as SNAP), when combined with data of nearby supernovae,…

Astrophysics · Physics 2014-10-13 Yun Wang , Veselin Kostov , Katherine Freese , Joshua A. Frieman , Paolo Gondolo

We forecast the expected cosmological constraints from a combination of probes of both the universal expansion rate and matter perturbation growth, in the form of weak lensing tomography, galaxy tomography, supernovae, and the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-10 Shahab Joudaki , Manoj Kaplinghat

Observational constraints are considered on a $w_{log}$CDM model of the dark energy equation of state, $w_{d}(z) = w_{0} + w_{a}\left( \frac{\ln(2+z)}{1+z} - \ln 2 \right)$, using the most recent cosmological datasets including DESI Baryon…

General Physics · Physics 2026-03-10 Saurabh Verma , Archana Dixit , Anirudh Pradhan , M. S. Barak
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