Public Interface

graph(proc::AbstractProcessDefinition)

Generate and return a ComputableDAGs.DAG, representing the computation for the squared matrix element of this scattering process, summed over spin and polarization combinations allowed by the process.

kwargs

• target::Symbol: Use one of the following:
  • :mat_el_sqsum to generate a graph calculating the square sum of the matrix elements
  • :diff_cs to generate a graph calculating the differential cross section
  • :diff_prob to generate a graph calculating the differential probability

number_of_diagrams(proc::AbstractProcessDefinition)

For a given QEDbase.AbstractProcessDefinition, returns the number of valid Feynman diagrams at tree-level. This is equivalent to

\[\frac{(M + 3N - 3)!}{(2N - 1)!} * E! * U! * T!\]

, where
$M \dots$ number of external photons,
$E \dots$ number of electron lines,
$U \dots$ number of muon lines,
$T \dots$ number of tauon lines, and
$N = E + U + T$.
An electron/muon/tauon "line" is a pair of incoming fermion and outgoing anti-fermion or vice versa.