T violation and CPT tests in neutral-meson systems

The review covers transitions M-0 <-> (M) over bar (0) in all neutral-meson systems that can show these weak-interaction transitions, M-0 = K-0, D-0, B-0 and B-s. The four systems are ideal laboratories for studying the discrete symmetries T and CPT. The properties of time reversal T are discussed in classical and quantum mechanics. T violation in K-0(K) over bar (0) transitions has been observed 1970 independent of assuming CPT symmetry by using the Bell-Steinberger unitarity relation. Improvements of this observation are reviewed including the latest results from 2013. They show with high significance that CP violation in K-0(K) over bar (0) transitions is only T violation without any CPT violation. Transitions in the other three systems do not show CP violation so far and, therefore, neither T nor CPT violation. The large observed CP violation in B-0 -> J/psi K-0 decays is presented to be compatible with only T and no CPT violation, the same for the significant but very small CP violation in decays K-0 -> pi pi, I = 2. (C) 2014 Elsevier B.V. All rights reserved.