Nuclear Data in Oklo and Time-Variability of Fundamental Coupling Constants

We re-examined Shlyakhter’s analysis of the Sm data in Oklo. With a special care of minimizing contamination due to the inflow of the isotope after the end of the reactor activity, we confirmed that his result on the time-variability of the fine-structure constant, |ά/α|≲10−17y−1, was basically correct. In addition to this upper bound, however, we obtained another result that indicates a different value of α 2 billion years ago. We add comments on the recent result from QSO’s.