Consistency constraints on ms from QCD dispersion relations and chiral perturbation theory in Kl3 decays

We use both old and new theoretical developments in QCD dispersion relation constraints on the scalar form factor in the decay K --> pi lv(l) to obtain constraints on the strange quark mass. The perturbative QCD side of the calculation incorporates up to four-loop corrections, while the hadronic side uses a recently developed parameterization constructed explicitly to satisfy the dispersive constraints. Using chiral perturbation theory(chi PT) as a model for soon-to-be measured data, we find a series of lower bounds on m(s) increasing with the accuracy to which one believes chi PT to represent the full QCD result. (C) 1998 Elsevier Science B.V. All rights reserved.