A model-independent test of the cosmic distance-duality relation using galaxy clusters and Type Ia supernovae matched pairs

The cosmic distance-duality relation (CDDR), expressed as $D_L\mathrm{/}{D}_A(1+z{)}^{-2}=1$, is a fundamental relation in cosmology connecting luminosity distance ($D_L$) and angular diameter distance ($D_A$). Any departure from this relation would indicate new physics such as photon non-conservation, cosmic opacity, or non-metric gravity. We perform a stringent, model-independent test of the CDDR using a matched sample of 38 galaxy clusters from the Bonamente et al. compilation and Type Ia supernovae from the Pantheon+ sample. Employing the matched-pair technique, we simultaneously constrain the CDDR-violation parameter $\eta$ and a possible redshift evolution of the SNe Ia absolute magnitude, parameterized as $M_B(z)=M_0+\epsilon z$. We assess the robustness against matching tolerance and further supplement the analysis with DESI 2024 BAO measurements. Our results yield $\eta =0.050_{-0.307}^{+0.348}$ and $\epsilon =-0.184_{-0.574}^{+0.724}$ (68% CL), showing no statistically significant evidence for CDDR violation or SNe Ia evolution. The conclusions remain unchanged with stricter matching criteria and the inclusion of DESI BAO data. We also derive a cosmology-independent calibration of $M_0=-19.460_{-0.124}^{+0.126}$ mag. The standard cosmological model remains robust under this model-independent scrutiny.