Quantum mechanics, Furry’s hypothesis, and a measure of decoherence in the K⁰K⁰ system

We consider strangeness correlations of the Einstein-Podolski-Rosen type in K⁰K⁰ pairs created in a J^PC=1^-- state as a function of time under the hypothesis that spontaneous decoherence takes place. We parametrize the degree of decoherence by a factor (1-ζ) which multiplies the quantum-mechanical interference terms occurring in the amplitudes for like and unlike strangeness events and discuss the dependence of this procedure on the basis chosen in K⁰-K⁰ space to which the interference terms correspond. Consequently, all statements about the “decoherence parameter” ζ inferred from experimental data are basis dependent as well. We illustrate this point by estimating the value of ζ for the two bases {K_L,K_S} and {K⁰,K⁰} with the help of recent data of the CPLEAR experiment.