Parton showers with quantum interference: leading color, with spin

Understand

We have previously described a mathematical formulation for a parton shower based on the approximation of strongly ordered virtualities of successive parton splittings.

• Quantum interference, including interference among different color and spin states, was included.
• A practical numerical implementation strategy was left unspecified.
• In a subsequent paper, we showed that if we add the further approximations of taking only the leading color limit and averaging over spins, we obtain a shower evolution that can be implemented as a Markov process.