Search for variability in Newton's constant using local gravitational acceleration measurements

TL;DR

This study investigates potential variations in Newton's constant using local gravitational acceleration data, improving previous methods by including measurement errors and considering multiple models, ultimately finding no strong evidence for variability.

Contribution

The paper improves previous analyses by incorporating measurement errors and compares multiple models, including linear variation, to search for changes in Newton's constant.

Findings

No evidence for periodic or linear variation in G.

Constant model is generally favored over sinusoidal models.

Linear variation of G is marginally preferred after accounting for intrinsic scatter.

Abstract

In a recent work, Dai (arXiv:2103.11157) searched for a variability in Newton's constant $G$ using the IGETS based gravitational acceleration measurements. However, this analysis, obtained from $\chi^2$ minimization, did not incorporate the errors in the gravitational acceleration measurements. We carry out a similar search with one major improvement, wherein we incorporate these aforementioned errors. To model any possible variation in the gravitational acceleration, we fit the data to four models: a constant value, two sinusoidal models, and finally, a linear model for the variation of gravitational acceleration. We find that none of the four models provides a good fit to the data, showing that there is no evidence for a periodicity or a linear temporal variation in the acceleration measurements. We then redid these analyses after accounting for an unknown intrinsic scatter. After this, we find that although a constant model is still favored over the sinusoidal models, the linear variation for $G$ is marginally preferred over a constant value, using information theory-based methods.