  John St. Bell was a physicist working most of his time at CERN and
contributing intensively and sustainably to the development of Particle Physics
and Collider Physics. As a hobby he worked on so-called "foundations of quantum
theory", that was that time very unpopular, even considered to be
scientifically taboo. His 1964-theorem, showing that predictions of local
realistic theories are different to those of quantum theory, initiated a new
field in quantum physics: quantum information theory. The violation of Bell's
theorem, for instance, is a necessary and sufficient criterion for generating a
secure key for cryptography at two distant locations. This contribution shows
how Bell's theorem can be brought to the realm of high energy physics and
presents the first conclusive experimental feasible test for weakly decaying
neutral mesons on the market. Strong experimental and theoretical limitations
make a Bell test in weakly decaying systems such as mesons and hyperons very
challenging, however, these systems show an unexpected and puzzling relation to
another big open question: why is our Universe dominated by matter, why did the
antimatter slip off the map? This long outstanding problem becomes a new
perspective via the very idea behind quantum information.
