Some considerations about mixing, oscillation phenomena and CP violation of different mass eigenstates

In the last twenty years there have been made many experimental and theoretical efforts to measure and verify the prediction of the Standard Model, as well as to put in evidence small deviation from these values. In the present paper, we discuss some aspects of possible regularities of the formalism of mixing and oscillation phenomena of the mass eigenstates in particle physics and possible consequences of hidden proprieties of the systems. In the literature representations of lepton flavour mixing with different parametrisation are used for three generations of leptons and quarks. Although these are mathematically equivalent, only one of them are likely to describe the underlying physics in a more transparent way, and particularly convenient in the analysis of experimental data or is able to establish a concordance with these ones. Flavour permutational symmetry of the mixing matrix, 'maximal democracy' and maximal CP violation give a simple and efficient way to understand the essential characteristics of the phenomena, with a minimum number of parameters. The deviations of the experimental data of these predicted values represent a simple clue to study phenomenologically the breaking of symmetries. The interplay of gravitation and linear superposition of different mass eigenstates, and their consequences on the oscillation clocks, phases and the physical observability are also briefly discussed. (authors)