  In the physics of flavor mixing, the flavor states are given by
superpositions of mass eigenstates. By using the occupation number to define a
multiqubit space, the flavor states can be interpreted as multipartite
mode-entangled states. By exploiting a suitable global measure of entanglement,
based on the entropies related to all possible bipartitions of the system, we
analyze the correlation properties of such states in the instances of three-
and four-flavor mixing. Depending on the mixing parameters, and, in particular,
on the values taken by the free phases, responsible for the CP-violation,
entanglement concentrates in preferred bipartitions. We quantify in detail the
amount and the distribution of entanglement in the physically relevant cases of
flavor mixing in quark and neutrino systems. By using the wave packet
description for localized particles, we use the global measure of entanglement,
suitably adapted for the instance of multipartite mixed states, to analyze the
decoherence induced by the free evolution dynamics on the quantum correlations
of stationary neutrino beams. We define a decoherence length as the distance
associated with the vanishing of the coherent interference effects among
massive neutrino states. We investigate the role of the CP-violating phase in
the decoherence process.
