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

Andronikos Paliathanasis

Published 2025-06-19Version 1

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.