Probing CPT violation in meson mixing by a noncyclic phase

The presence of noncyclic phases is revealed in the time evolution of mixed meson systems. Such phases are related to the parameter z describing the CPT violation; moreover, a nonzero phase difference between particle and antiparticle arises only in the presence of CPT symmetry breaking. Thus, a completely new test for the CPT invariance can be provided by the study of such phases in mixed mesons. Systems which are particularly interesting for such an analysis are the B-s(0) - (B) over bar (0)(s) and the K-0 - (K) over bar (0) ones. In order to introduce noncyclic phases, some aspects of the formalism describing the mixed neutral mesons are analyzed. Since the effective Hamiltonian of systems like K-0 - (K) over bar (0), B-0 - (B) over bar (0), B-s(0) - (B) over bar (0)(s), D-0 - (D) over bar (0)(s) is non-Hermitian and non-normal, it is necessary to diagonalize it by utilizing the rules of non-Hermitian quantum mechanics.