Cosmological measurement of the gravitational constant $G$ using the CMB, the BAO and the BBN

TL;DR

This paper uses the latest cosmological data from Planck, DESI, and BBN to measure the gravitational constant G with 1.8% precision, aligning well with laboratory results and demonstrating robustness across different cosmological models.

Contribution

It provides the first high-precision cosmological measurement of G using combined CMB, BAO, and BBN data, improving accuracy over previous estimates.

Findings

Achieved 1.8% precision on G measurement

Measurement consistent with laboratory values within one standard deviation

Robust against variations in cosmological model assumptions

Abstract

Recent cosmological observations have provided numerous new observations with increasing precision that have led to the era of precision cosmology. The exquisite quality of these observations opens new possibilities towards measuring fundamental constants with good precision and at scales which are complementary to the laboratory ones. In particular, the cosmic microwave background (CMB) temperature and polarization spectra contain a wealth quantity of information, well beyond the basic cosmological parameters. In this paper, we update the precision on a cosmological determination of $G$ by using the latest Planck data release (PR4) in combination with the latest baryon acoustic oscillation (BAO) from the Dark Energy Spectroscopic Instrument (DESI) data release 1 and the primordial Helium fraction from BBN. We demonstrate a precision of $1.8\%$, corresponding to a $\sim25\%$ improvement compared to the literature. This measurement is compatible with laboratory ones within one standard deviation. Finally, we show that this cosmological measurement of $G$ is robust against several assumptions made on the cosmological model, in particular when considering a non-standard dark energy fluid or non-flat models.