I have been reading about the MSW effect in neutrinos from supernovae. In some papers, it's assumed the "adiabatic case" which, according to the book "Neutrino Physics and Astrophysics" by Giunti, implies that the transitions between $\nu_1^M,\nu_2^M$ are negligible. However, I do not understand what he is writing about. I thought that the transitions are between flavor states, not between mass states.
Moreover, in Wikipedia, it is said: "When neutrinos go through the MSW resonance, the neutrinos have the maximal probability to change their flavor, but it happens that this probability is negligibly small—this is sometimes called propagation in the adiabatic regime," which I also do not understand: the probability is maximal BUT is negligible?
I would really appreciate any clarification.
