On the origin of the CDDR violation

TL;DR

This paper proposes a new method to investigate the origin of potential violations in the Cosmic Distance Duality Relation (CDDR) by analyzing observational data from SNIa, BAO, and gas mass fraction measurements, highlighting possible links to new physics.

Contribution

It introduces a novel approach to identify the source of CDDR violations using combined observational datasets and different parameterizations, focusing on the role of angular diameter distance.

Findings

Sets involving $f_{gas}$ show less deviation, indicating potential new physics in angular diameter distance.

The difference between data sets suggests violations may originate from physics affecting $d_A$.

The method constrains $ exteta$ using multiple observational probes and parameterizations.

Abstract

The investigation of any violation in the Cosmic Distance Duality Relation (CDDR) is one of the most important sources of investigation for a new physic. In this paper we propose a new method to find the origin of a possible violation on the CDDR. Such violation is defined from the equation $\frac{d_L}{d_A(1+z)^2} = \eta$, with $\eta \neq 1$. We analyze the observational constraints from SNIa, BAO and $f_{gas}$ for the parameter $\eta$ using three different parameterizations. We create three data sets with the following combinations: (Set I) $d_L$ data from SNIa and $d_A$ data from BAO measurements, (Set II) $d_L$ data from $f_{gas}$ and $d_A$ from BAO measurements and (Set III) $d_L$ from SNIa and $d_A$ from $f_{gas}$ measurements. The sets have 18 points and a redshift difference between the observational pairs of $\Delta z \leq 0.08$. It is found that the difference between Sets I and II is up to five times higher than Sets I and III, what suggest that a violation in the CDDR come from a new physics related with the angular diameter distance.