FIELD THEORY APPROACH TO $K^0-\overline{K^0}$ AND $B^0-\overline{B^0}$ SYSTEMS

Quantum field theory provides a consistent framework to deal with unstable particles. We present here an approach based on field theory to describe the production and decay of unstable [Formula: see text] and [Formula: see text] mixed systems. The formalism is applied to compute the time evolution amplitudes of K0 and [Formula: see text] studied in DAPHNE and CPLEAR experiments. We also introduce a new set of parameters that describe CP violation in K→ππ decays without recourse to isospin decomposition of the decay amplitudes.