A preference for dynamical phantom dark energy using one-parameter model with Planck, DESI DR1 BAO and SN data

Understand

Baryon Acoustic Oscillation (BAO) provides a powerful tool to measure cosmic expansion and consequently the nature of the Dark Energy (DE).

• Recent precise BAO measurements by Dark Energy Spectroscopic Instrument data release 1 (DESI DR1), when combined with Cosmic Microwave Background (CMB) data from Planck and Supernovae of Type Ia (SN Ia), favor evolving dark energy over cosmological constant.
• This result is strongly related to the assumed priors on the Chevallier-Polarski-Linder (CPL) parameterization of DE.
• We test another parametrization which introduces two free parameters $n$ and $\alpha$, only $n$ is independent.