A new diagnostic for the null test of dynamical dark energy in light of DESI 2024 and other BAO data

Understand

We introduce a new diagnostic for the null tests of dynamical dark energy alongside two other combined equivalent diagnostics.

• These diagnostics are useful, especially when we include anisotropic baryon acoustic oscillation (BAO) data in an analysis, to quantify the deviations from the standard $\Lambda$CDM model.
• We also consider another diagnostic for isotropic BAO observations.
• These null tests are independent of any late-time dark energy model or parametrization.