Testing the b-CPL dynamical dark energy model with recent cosmological data

Koussour M. Donmez O. Bekov S. Altaibayeva A. Saginbay A. Muminov S. Rayimbaev J.
March 2026 Elsevier B.V.

Journal of High Energy Astrophysics
2026 #51

We introduce and constrain a new parameterization for the dark energy equation of state, the b-CPL model, defined as ω_b-CPL(z)=ω₀+ω₁z1+bz, which extends the standard CPL framework by including a parameter b . This additional degree of freedom provides enhanced flexibility to capture potential deviations from standard dynamical dark energy behavior, while reducing to CPL for b=1 and to ΛCDM in specific limits. Notably, the b-CPL parameterization remains finite at future times, avoiding divergences. Using a combined dataset of cosmic chronometers, PantheonPlus Type Ia supernovae, and DESI baryon acoustic oscillations, we perform a Markov Chain Monte Carlo analysis to constrain the cosmological parameters for the b-CPL, CPL, and ΛCDM models. The b-CPL model yields a more negative present-day equation of state (ω₀=−1.12_−0.20^+0.31) and a higher matter density (Ω_m⁰=0.332_−0.049^+0.065) compared to CPL and ΛCDM. Model selection statistics based on the reduced chi-square, AIC, and BIC indicate that b-CPL is strongly preferred, showing decisive evidence over ΛCDM (ΔAIC=−41.83, ΔBIC=−30.91) and significant improvement over CPL (ΔAIC=−26.05, ΔBIC=−9.66). Physically, the b-CPL model exhibits a mild redshift evolution of the EoS parameter and tends to remain in the phantom regime (ω₀<−1) at present, although within 68 % confidence level, the quintessence region (ω₀>−1) is still allowed. It predicts the strongest present-day acceleration (q₀=−0.62±0.27), and features a rapidly decaying dark energy density Ω_de( z ) at high redshift. These results position b-CPL as a statistically robust and physically consistent framework for dynamical dark energy, bridging the gap between the simplicity of ΛCDM and the stronger evolution allowed by CPL.

And cosmological constraints , b-CPL parameterization , Dark energy , Equation of state , Model selection

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Department of Physics, University of Hassan II, Casablanca, Morocco
College of Engineering and Technology, American University of the Middle East, Egaila 54200, Kuwait
Department of General and Theoretical Physics, L.N. Gumilyov, Eurasian National University, Astana, 010008, Kazakhstan
Mamun University, Bolkhovuz Street 2, Khiva, 220900, Uzbekistan
Institute of Fundamental and Applied Research, National Research University TIIAME, Kori Niyoziy 39, Tashkent, 100000, Uzbekistan
University of Tashkent for Applied Sciences, Str. Gavhar 1, Tashkent, 100149, Uzbekistan
Tashkent State Technical University, Universitet Str. 2, Tashkent, 100095, Uzbekistan
National University of Uzbekistan, Universitet Str. 4, Tashkent, 100174, Uzbekistan
Urgench State University, Kh. Alimjan Str. 14, Urgench, 221100, Uzbekistan

Department of Physics
College of Engineering and Technology
Department of General and Theoretical Physics
Mamun University
Institute of Fundamental and Applied Research
University of Tashkent for Applied Sciences
Tashkent State Technical University
National University of Uzbekistan
Urgench State University

10 лет помогаем публиковать статьи Международный издатель

Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026