Neutral kaons in medium: decoherence effects

We consider departures from Hamiltonian dynamics in the evolution of neutra l kaons due to their interactions with environment that generate entangleme nt among them. We propose a phenomenological model of stochastic re-scatter ing and estimate the coefficients of the effective Hamiltonian and decohere nce terms. Finally we analyze the interplay between the weak interaction an d matter effects and propose the observables suitable to measure the matter characteristics of CPT violation and decoherence. (C) 2001 Published by El sevier Science B.V.