Can strong correlations be experimentally revealed for κ-mesons?

In 1964 the physicists John St. Bell working at CERN took the 1935-idea of Einstein-Podolsky-Rosen seriously and found that all theories based on local realism have to satisfy a certain inequality, nowadays dubbed Bell's inequality. Experiments with ordinary matter systems or light show violations of Bell's inequality favouring the quantum theory though a loophole free experiment has not yet been performed. This contribution presents an experimentally feasible Bell inequality for systems at higher energy scales, i.e. entangled neutral K-meson pairs that are typically produced in Phi-mesons decays or proton-antiproton annihilation processes. Strong requirements have to be overcome in order to achieve a conclusive tests, such a proposal was recently published. Surprisingly, this new Bell inequality reveals new features for weakly decaying particles, in particular, a strong sensitivity to the combined charge-conjugation-parity (CP) symmetry. Herewith, a puzzling relation between a symmetry breaking for mesons and Bell's inequality-which is a necessary and sufficient condition for the security of quantum cryptography protocols-is established. This becomes the more important since CP symmetry is related to the cosmological question why the antimatter disappeared after the Big Bang.