Parton showers with quantum interference: leading color, spin averaged

TL;DR

This paper presents a leading color, spin-averaged formulation of a quantum interference-inclusive parton shower, aligning with common Monte Carlo methods while retaining soft gluon interference effects.

Contribution

It extends previous quantum interference parton shower models by incorporating leading color and spin averaging approximations, making it comparable to standard Monte Carlo implementations.

Findings

The leading color, spin-averaged shower is similar to existing formulations.

Soft gluon interference effects are preserved under these approximations.

Differences between this formalism and other models are discussed.

Abstract

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, is included. In this paper, we add the further approximations of taking only the leading color limit and averaging over spins, as is common in parton shower Monte Carlo event generators. Soft gluon interference effects remain with this approximation. We find that the leading color, spin averaged shower in our formalism is similar to that in other shower formulations. We discuss some of the differences.