Probing dark energy dynamics through a new CPL-type Om(z) parametrization in FLRW Universe
Abstract
In this work, we investigate a CPL-type Om(z) parametrization given by Om(z)=l+m(z/(1+z)) to study the evolution of dark energy and possible deviations from the standard ΛCDM cosmology. The model reduces to the flat ΛCDM scenario for m=0, while m≠0 indicates dynamical evolution. The free parameters are constrained using Pantheon+SH0ES (PPS), Cosmic Chronometer (CC), and DESI BAO DR2 observations through Markov Chain Monte Carlo analysis. The obtained constraints yield 72.48≲ H0≲72.97 km s−1 Mpc−1, while the evolution parameter remains negative for all dataset combinations, leading to decreasing Om(z) evolution and favoring quintessence-like behaviour. The combined PPS+CC+DR2 analysis shifts the evolution closer to the ΛCDM limit. The statistical analysis based on χ2, AIC, and BIC indicates that the proposed model remains statistically competitive with ΛCDM. The deceleration parameter and total equation of state are further analyzed to examine the cosmic evolution. The transition from deceleration to acceleration occurs within ztr≈0.66−1.01, while the present values vary within −0.459≲ q0≲−0.325 and −0.639≲ω0≲−0.550 depending on the datasets. Overall, the proposed parametrization provides a flexible framework for studying late-time cosmic evolution.
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BibTeX
@misc{kumar2026probing,
title = {{Probing dark energy dynamics through a new CPL-type $Om(z)$ parametrization in FLRW Universe}},
author = {D. Revanth Kumar and Santosh Kumar Yadav and S. A. Kadam},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.04229},
eprint = {2609.04229},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.04229},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Probing dark energy dynamics through a new CPL-type Om(z) parametrization in FLRW Universe
AU - D. Revanth Kumar
AU - Santosh Kumar Yadav
AU - S. A. Kadam
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.04229
UR - https://arxiv.org/abs/2609.04229
AB - In this work, we investigate a CPL-type Om(z) parametrization given by Om(z)=l+m(z/(1+z)) to study the evolution of dark energy and possible deviations from the standard ΛCDM cosmology. The model reduces to the flat ΛCDM scenario for m=0, while m≠0 indicates dynamical evolution. The free parameters are constrained using Pantheon+SH0ES (PPS), Cosmic Chronometer (CC), and DESI BAO DR2 observations through Markov Chain Monte Carlo analysis. The obtained constraints yield 72.48≲ H_0≲72.97 km s^−1 Mpc^−1, while the evolution parameter remains negative for all dataset combinations, leading to decreasing Om(z) evolution and favoring quintessence-like behaviour. The combined PPS+CC+DR2 analysis shifts the evolution closer to the ΛCDM limit. The statistical analysis based on χ^2, AIC, and BIC indicates that the proposed model remains statistically competitive with ΛCDM. The deceleration parameter and total equation of state are further analyzed to examine the cosmic evolution. The transition from deceleration to acceleration occurs within z_tr≈0.66−1.01, while the present values vary within −0.459≲ q_0≲−0.325 and −0.639≲ω_0≲−0.550 depending on the datasets. Overall, the proposed parametrization provides a flexible framework for studying late-time cosmic evolution.
ER -