Srednicki — Quantum Field Theory · Problem 48.3

Canonical Quantization of Scalar Fields — Mark Srednicki

Physics — QFT · spin-averaged-cross-sections-crossing-symmetry

Problem

Compute

\langle|\mathcal{T}|^2\rangle

for

e^-e^- \to e^-e^-

. You should find that your result is the same as that for

e^+e^- \to e^+e^-

, but with

s \leftrightarrow u

. This is another example of crossing symmetry.