An electron and a positron collide and annihilate through a virtual photon to produce…
PHYSICS · Subjective · Fermi University Physics · Particle Physics & Quantum Fields · Interacting fields, Feynman diagrams and QED · Interacting fields, Feynman diagrams and QED
Particle Physics, Ch Exchange, range and coupling: diagrams as bookkeeping
Problem
An electron and a positron collide and annihilate through a virtual photon to produce a τ+τ− pair: e+e−→τ+τ−. (a) Describe the Feynman diagram for this process as bookkeeping, naming every line (with arrow direction for particles and antiparticles), the internal line, and each vertex. (b) State which vertex type is used, and how many times. (c) State whether electron lepton number Le and tau lepton number Lτ are separately conserved at each vertex, or only their sum.