Modified CPL dark energy model in light of the latest cosmological observations

We investigate the cosmological implications of the modified Chevallier–Polarski–Linder (MCPL) parametrization as an alternative framework for dark energy dynamics. This model extends the standard CPL form by introducing an additional parameter that ensures [Formula: see text] remains finite as [Formula: see text], thereby enabling a consistent description at late times. Using 31 cosmic chronometer [Formula: see text] measurements, 1701 Pantheon+ (PP) SNe Ia (calibrated with SH0ES), and 12 DESI BAO data points, we constrain the model through a comprehensive Markov Chain Monte Carlo (MCMC) analysis. The results yield [Formula: see text][Formula: see text]km s[Formula: see text] Mpc[Formula: see text] (from [Formula: see text] and DESI) and [Formula: see text][Formula: see text]km s[Formula: see text][Formula: see text]Mpc[Formula: see text] (from PP+SH0ES), reproducing the Hubble tension. Moreover, the evolution of [Formula: see text] exhibits both phantom-like and quintessence-like regimes depending on the dataset, approaching [Formula: see text] in the far future. The transition redshift [Formula: see text] aligns with observational expectations, and the [Formula: see text] diagnostic indicates clear deviations from [Formula: see text]CDM, reflecting the dynamical nature of dark energy within this parametrization. Furthermore, AIC and BIC comparisons indicate that the MCPL model performs comparably to [Formula: see text]CDM, with a moderate AIC preference in the case of PP+SH0ES. This suggests that the MCPL model constitutes a competitive, though not universally preferred, alternative to the standard [Formula: see text]CDM scenario.

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