  The subject of this thesis is the study of dissipative dynamics and their
properties in particle physics, dealing with neutral B-mesons, neutron
interferometry and neutrino physics. Modified expressions for the relevant
phenomenological quantities characterizing these systems are obtained.
Moreover, the models presented in this work offer the possibility of direct
tests of some basic properties of reduced dynamics (in particular the notion of
complete positivity) since they represent concrete systems amenable to actual
experiments.
