Inferring dark energy properties from the scale factor parametrization

We propose and implement a novel test to assess deviations from well-established concordance Λ CDM cosmology while inferring dark energy properties. In contrast to the commonly implemented parametric forms of the dark energy equation-of-state (EoS), we test the validity of the cosmological constant on the more fundamental scale factor [a(t)] which determines the expansion rate of the Universe. We constrain our extended "general model"using the late-time observables. The posterior of the dark energy EoS is mainly constrained to be quintessencelike naturally excluding physically unviable regions such as phantom crossings or exponential growth.