Constraints on extended Bekenstein models from cosmological, astrophysical, and local data

TL;DR

This paper constrains extended Bekenstein models that propose a scalar field causing variations in the fine-structure constant, using diverse cosmological, astrophysical, and local data, ruling out couplings above parts per million.

Contribution

It provides the first comprehensive constraints on various versions of the Bekenstein model by analyzing their full cosmological evolution against extensive observational data.

Findings

Couplings of the order of parts per million are excluded.

Strong restrictions are imposed on theories involving variations of the fine-structure constant.

The analysis covers multiple extensions of the Bekenstein model.

Abstract

Searching for variations of nature's fundamental constants is a crucial step in our quest to go beyond our current standard model of fundamental physics. If they exist, such variations will be very likely driven by the existence of a new fundamental field. The Bekenstein model and its extensions introduce such a scalar field in a purely phenomenological way, inducing a variation of the fine-structure constant on cosmological scales. This theoretical framework is as simple and general as possible while still preserving all the symmetries of standard quantum electrodynamics. When allowing for couplings to the other sectors of the Universe, such as baryons, dark matter, and the cosmological constant, the Bekenstein model is expected to reproduce the low energy limits of several grand unification, quantum gravity, and higher dimensional theories. In this work, we constrain different versions of the Bekenstein model by confronting the full cosmological evolution of the field with an extensive set of astrophysical, cosmological, and local measurements. We show that couplings of the order of parts per million (ppm) are excluded for all the cases considered, imposing strong restrictions on theoretical frameworks aiming to deal with variations of the fine-structure constant.