Light Higgs particle in decays of K and η mesons

We present a complete theoretical analysis of the decay amplitude K → πH and η → πH, where H is a hypothetical light Higgs particle. The analysis is based on the consistent use of the effective chiral lagrangian technique. In the K → πH transition the so-called "second constant" - the last undetermined part of the amplitude - is evaluated. Its contribution is shown to be relatively small and not important numerically. The η → πH amplitude is of order p⁴. We demonstrate that it is reliably calculable in terms of low-energy constants which are known from the phenomenology of the Goldstone mesons.