PHYSICS · Multi-part · Fermi University Physics · Particle Physics & Quantum Fields · Interacting fields, Feynman diagrams and QED · Electroweak theory and the Standard Model
Particle Physics, Ch Exchange, range and coupling: diagrams as bookkeeping
Problem
A diagram is drawn with time running to the right. An incoming u quark line and an incoming dˉ quark line meet at a single vertex and turn into one internal wavy line. That internal line ends at a second vertex, from which an outgoing μ+ line and an outgoing νμ line emerge.
((a)) Identify the process this diagram represents, both as a quark-level reaction and as the corresponding hadron decay.
((b)) Name the vertex type used at each of the two vertices, and justify the choice from the electric charges involved.
((c)) State the number of vertices, and name one conservation law that fixes the charge of the internal line.