New Expansion Rate Anomalies at Characteristic Redshifts Geometrically Determined using DESI-DR2 BAO and DES-SN5YR Observations

Understand

We perform a model-independent reconstruction of the cosmic distances using the Multi-Task Gaussian Process (MTGP) framework as well as knot-based spline techniques with DESI-DR2 BAO and DES-SN5YR datasets.

• We calibrate the comoving sound horizon at the baryon drag epoch $r_d$ to the Planck value, ensuring consistency with early-universe physics.
• With the reconstructed cosmic distances and their derivatives, we obtain seven characteristic redshifts in the range $0.3 \leq z \leq 1.7$.
• We derive the normalized expansion rate of the Universe $E(z)$ at these redshifts.