Precision constraints on new dark energy parametrization from DESI BAO DR2

In this paper, we investigate a new parametrization of the dark energy equation of state (EoS) with a single parameter for a barotropic fluid that deviates from the standard [Formula: see text]CDM cosmology. We derive observational constraints on the model parameters using recent datasets including Observational Hubble Data (OHD), Pantheon+SH0ES (PPS), and Dark Energy Spectroscopic Instrument Baryon Acoustic Oscillations Data Release 2 (DESI BAO DR2). We constrain the best fit value of the parameter as [Formula: see text] at 68% CL from joint analysis, which is non-null and suggests deviations from the cosmological constant. The model accommodates varying values of Hubble constant from different datasets and the joint analysis yields [Formula: see text] km s −1 Mpc −1 at 68% CL. We examine the physical behavior of the model by analyzing the deceleration parameter, the age of the universe, and the [Formula: see text] diagnose. The deceleration parameter confirms a smooth transition from the past deceleration phase to the present cosmic acceleration as well as and also a second future transition back to deceleration, when PPS data is employed.