Scattering Processes and the S-Matrix
N. Cabibbo, Luciano Maiani, Omar Benhar · 2025
This Chapter is devoted to the description of scattering processes based on reduction formulae of Lehman, Szymanzik and Zimmermann (LSZ). Within this scheme, a link is established between the q-point Green&s;s function and the S-matrix elements yielding the amplitude of a process involving p initial-state particles and (q − p) final-state particles. The formalism is based on use of asymptotic “in” and “out” states, describing the system in the