Probing unification scenarios with atomic clocks

TL;DR

This paper uses atomic clock measurements to test unification theories by constraining variations in fundamental constants, providing updated null results that support but do not strongly limit these models.

Contribution

It offers the first comprehensive analysis of atomic clock data to constrain coupled variations of fundamental constants within unification scenarios.

Findings

Null results for proton-to-electron mass ratio variation

Null results for gyromagnetic factor variation

Results compatible with unification theories but with parameter degeneracies

Abstract

We discuss the usage of measurements of the stability of nature's fundamental constants coming from comparisons between atomic clocks as a means to constrain coupled variations of these constants in a broad class of unification scenarios. After introducing the phenomenology of these models we provide updated constraints, based on a global analysis of the latest experimental results. We obtain null results for the proton-to-electron mass ratio ${\dot\mu}/{\mu}=(0.68\pm5.79)\ti mes10^{-16}\, {\rm yr}{}^{-1}$ and for the gyromagnetic factor ${\dot g_p}/{g_p} =(-0.72\pm0.89)\times10^{-16}\, {\rm yr}{}^{-1}$ (both of these being at the 95 % confidence level). These results are compatible with theoretical expectations on unification scenarios, but much freedom exists due to the presence of a degeneracy direction in the relevant parameter space.