Limits on variability of the fundamental physical constants from radionuclide data and primary nucleosynthesis model

This article reviews recent work on the possible time variability of coupling constants of the fundamental interactions, such as the fine structure constant α≡e2/hc and the corresponding quantities for the strong and weak interactions. New limits on their time variations have been obtained. Use of separate evaluations for the 187Re half-life by two measurement methods - an analysis of the Re-Os isotopic composition in meteorites and a direct measurement of 187Re specific activity in laboratory - leads to a conclusion that the 187Re decay constant has not increased more than by 10% for 4x109 yr and it has not decreased more than by 4% for the same period. This gives a strict limit on the possible change of the fine structure constant: |dα/αdt|≤l,3x10-15 yr-1 and much weaker limit on the variation of the weak interaction coupling constant: |dαw/αwdt|≤1,3x10-11 yr-1. An analysis of the helium yield within the framework of the primary nucleosynthesis model leads to stronger limitation of the variability of the latter constant: |dαw/αwdt|≤4x10-12 yr-1