Spin-Dependent Antenna Splitting Functions

TL;DR

This paper derives spin-dependent splitting functions for antenna-based parton showers, addressing how to replace traditional Altarelli-Parisi functions in helicity-specific radiation processes for initial and final states.

Contribution

It provides a detailed formulation of spin-dependent antenna splitting functions applicable to both initial- and final-state emissions in QCD parton showers.

Findings

Derived explicit spin-dependent splitting functions

Applicable to both initial- and final-state emissions

Enhances accuracy of antenna shower simulations

Abstract

We consider parton showers based on radiation from QCD dipoles or `antennae'. These showers are built from 2->3 parton splitting processes. The question then arises of what functions replace the Altarelli-Parisi splitting functions in this approach. We give a detailed answer to this question, applicable to antenna showers in which partons carry definite helicity, and to both initial- and final-state emissions.