Observational Constraints on Scalar Field--Matter Interaction in Weyl Integrable Spacetime

TL;DR

This paper tests a Weyl Integrable Spacetime cosmological model with observational data, finding it fits current data better than standard Lambda-CDM and suggests a weak to moderate preference for this alternative gravity theory.

Contribution

It introduces a scalar field-matter interaction in Weyl Integrable Spacetime and demonstrates its compatibility and slight preference over Lambda-CDM using multiple observational datasets.

Findings

Weyl Integrable Spacetime fits observational data better than Lambda-CDM.

The model shows a weak to moderate statistical preference over Lambda-CDM.

The scalar field-matter interaction is consistent with current cosmological observations.

Abstract

We test an analytic cosmological solution within the framework of Weyl Integrable Spacetime using current observational data. In this model, dark energy is described by a pressureless fluid, while a scalar field arises naturally through the definition of the connection. This gravitational theory reveals a Chameleon Mechanism leading to a nonzero interaction between the scalar field and the matter sector. This model extends the standard $\Lambda $CDM cosmology by introducing one additional degree of freedom, allowing for deviations from $\Lambda$CDM dynamics. For the observational constraints we consider the Supernova data of Pantheon+ collaboration, the Cosmic Chronometers, the Baryonic Acoustic Oscillators of DESI DR2 collaboration and the gamma-ray bursts. We find that Weyl Integrable Spacetime fits the data in a better way than the $\Lambda$CDM. When all datasets are considered, the statistical comparison indicates a weak to moderate preference for Weyl Integrable Spacetime according to the Akaike Information Criterion and Jeffrey's scale for the Bayesian evidence.