Irreversible Quantum Mechanics in the Neutral K-System

The neutral Kaon system is used to test the quantum theory of resonance scattering and decay phenomena. The two dimensional LeeOehme-Yang theory with complex Hamiltonian is obtained by truncating the complex basis vector expansion of the exact theory in Rigged Hilbert space. This can be done for K1 and K2 as well as for KS and KL, depending upon whether one chooses the (self-adjoint, semibounded) Hamiltonian as commuting or non-commuting with CP. As an unexpected curiosity one can show that the exact theory (without truncation) predicts long-time 2π decays of the neutral Kaon system even if the Hamiltonian conserves CP. ∗ e-mail: [email protected]