2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/48712Why Hand Waving? All calculations in books describe oscillations in time. But real experiments don't measure time. Hand waving is used to convert the results of a "gedanken time experiment" to the result of a real experiment measuring oscillations in space. Right hand waving gives the right answer; wrong hand waving gives the wrong answer. Many papers use wrong handwaving to get wrong answers. This talk explains how to do it right and also answers the following questions: 1. A neutrino which is a mixture of two mass eigenstates is emitted with muon in the decay of a pion at rest. This is a a "missing mass experiment" where the muon energy determines the neutrino mass. Why are the two mass states coherent? 2. A neutrino which is a mixture of two mass eigenstates is emitted at time t=0. The two mass eigenstates move with different velocities and arrive at the detector at different times. Why are the two mass states coherent? 3. A neutrino is a mixture of two overlapping wave packets with different masses moving with different velocities. Will the wave packets eventually separate? If yes, when?46 pagesHigh Energy Physics - Phenomenologytext