Orateur
Description
We investigate potential variations in fundamental constants—such as the fine-structure constant (α), the proton-to-electron mass ratio (μ), and Newton’s gravitational constant (G)—as a probe of physics beyond the Standard Model. Using high-resolution ultraviolet spectra of Fe V in the white dwarf G191-B2B from HST/STIS, combined with precise laboratory data, we constrain the time variation of G to $\dot{G}/G = (0.038 \pm 0.118) \times 10^{-15}~\text{yr}^{-1}$ in a gravitational potential ~10⁴ times that of Earth. These findings, alongside constraints from other astrophysical and cosmological probes, test the constancy of nature’s laws across space-time, challenge the equivalence principle, and provide insights into new physics such as scalar fields, extra dimensions, or varying coupling frameworks.
