Theory of Neutrino Oscillations

We present a derivation of the flavor neutrino states which describe neutrinos produced or detected in charged-current weak-interaction processes, including those operating in neutrino oscillation experiments. We also present a covariant derivation of the probability of neutrino oscillations which is consistent with the fact that flavor is Lorentz-invariant. Finally, we clarify the negative answers to three commonly asked questions: "Do charged leptons oscillate?"; "Is the standard phase wrong by a factor of 2?" "Are flavor neutrinos described by Fock states?".