An upper limit for the induced scalar coupling constant ƒ s

Abstract

Recently, two comprehensive works analysing the available extensive data on superallowed Fermi β-decays have been published by Raman-Walkiewicz-Behrens and Hardy-Towner. We reviewed such compilations to investigate (a) the consistency of the data with CVC theory and (b) the sensitivity of the F t values to different ways of evaluating the integrated statistical rate function. No evidence for sizeable mesonic exchange effects was found. It is shown that using the available data for 0 + → 0 + superallowed transitions it is possible to extract a meaningful upper limit for the induced scalar coupling constant ƒ s. For instance, considering the F t values reported by Raman-Walkiewicz-Behrens we obtained ƒ s /ƒ v = (−0.14± 1.55) × 10 −4 . The limit imposed by this value is almost one order smaller than the order l/ M which one would expect in the case where CVC should not hold.