Oral comunication
C. J. A. P. Martins
Abstract
Cosmography is a model-independent phenomenological approach to observational cosmology, re-
lying on Taylor series expansions of physical quantities as a function of the cosmological redshift or
analogous variables. A recent work [Martins et al. Phys. Lett. B827 (2022) 137002] developed the
formalism for a cosmographic analysis of astrophysical and local measurements of the fine-structure
constant, α, and provided first constraints on the corresponding parameters. Here we update the
earlier work, both by including more recent measurements of α and by extending it to the proton-
to-electron mass ratio, the proton gyromagnetic ratio, and various combinations of the three en-
abling the addition of the corresponding measurements to the analysis. We place stringent model-
independent constraints on the first two terms of these cosmographic series, ranging from the parts
per billion to the parts per million level. We illustrate the benefits of this approach with two specific
applications: cosmographic constraints on a broad class of Grand Unified Theories in which varying
fundamental constants unavoidably occur, and a discriminating test between freezing and thawing
dark energy models.
IberiCos 2025
Department of Physics (University of Coimbra), Portugal
2025 April
