S. M. Joćo, C. J. A. P. Martins, I. S. A. B. Mota, P. M. T. Vianez
Astrophysical tests of the stability of Nature's fundamental couplings are a key probe of the standard paradigms in fundamental physics and cosmology. In this report we discuss updated constraints on the stability of the fine-structure constant α and the proton-to-electron mass ratio μ=mp/me within the Galaxy. We revisit and improve upon the analysis by Truppe et al.  by allowing for the possibility of simultaneous variations of both couplings and also by combining them with the recent measurements by Levshakov et al. . By considering representative unification scenarios we find no evidence for variations of α at the 0.4 ppm level, and of μ at the 0.6 ppm level; if one uses the  bound on μ as a prior, the α bound is improved to 0.1 ppm. We also highlight how these measurements can constrain (and discriminate among) several fundamental physics paradigms.
Astrophysical observation, Fundamental couplings, Unification scenarios
Physics Letters B
Volume 749, Page 389