The superposition of flavour (and mass) eigenstates of neutral mesons is a stunning example of quantum mechanics in the Standard Model. The phenomenological consequence is a small mass difference between the mass eigenstates, and time-dependent oscillations of the flavour eigenstates. In this seminar the legacy measurement of the mass difference (delta-ms) in the B0s system is shown and a significant new result for the D0 system will be reported.
Michelangelo Mangano, Monica Pepe-Altarelli and Pedro Silva.