MSW effect in quantum field theory - art. no. 073012

We show in detail the general relationship between the Schrodinger equation approach to calculating the MSW: effect and the quantum field-theoretical S-matrix approach. We show the precise form a generic neutrino propagator m ust have to allow a physically meaningful "oscillation probability" to be d ecoupled from neutrino production fluxes and detection cross sections, and explicitly list the conditions-not realized in cases of current experimenta l interest-in which the field theory approach would be useful. [S0556-2821( 99)01619-7].