Uploaded October 2019 | Updated September 2026, 3 hours ago

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In this video, I show you how to derive the tree level pair annihilation cross section in quantum electrodynamics.

My Quantum Field Theory Lecture Series:
youtube.com/playlist?list=PLSpklniGdSfSsk7BSZjONcfhRGKNa2uou

Deriving the Feynman rules video:
youtube.com/watch?v=ToL-37wnHZw

General differential scattering cross section formula derivation:
youtube.com/watch?v=HqOetWTHeGs

Superfluid Helium Resonance Experiment video:
youtu.be/unUNQNmuvUQ

Note: There are a couple of typos in this videos between 11:05 and 11:19. In the first typo, instead of typing k_1dotk_2 = |k_1|(m+E-|p|cos(theta)), I accidentally typed k_1dotk_2 = |k_1|^2(m+E-|p|cos(theta)). The other typo consist of this error being propagated through to the next step. It is not propagated any farther, however, so most of the calculation is unaffected.