Suppose I consider an interacting theory, say QED (with electrons and photons). Let, free electrons, I mean the quanta of the free Dirac Lagrangian. The dressed electron differs from the free electron by a renormalized mass and renormalized charge.
When we consider scattering, do we consider scattering between free Dirac electrons or renormalized electrons? In other words, I want to understand whether the asymptotic momentum eigenstates in the LSZ formalism, are electrons of the free theory or dressed electrons.