A simple shower and matching algorithm

TL;DR

This paper introduces a simple formalism for parton-shower Markov chains, addressing uncertainties and proposing a matching method to align generated events with higher-order perturbative calculations, implemented in the VINCIA code.

Contribution

It presents a new matching formalism for parton showers that reproduces NLO distributions and explores ambiguities, along with a generalized hadronization cutoff.

Findings

Implemented in the VINCIA code for final-state gluon showers.

Achieved better agreement with NLO calculations.

Provided a framework to reduce uncertainties in parton-shower simulations.

Abstract

We present a simple formalism for parton-shower Markov chains. As a first step towards more complete uncertainty bands, we incorporate a comprehensive exploration of the ambiguities inherent in such calculations. To reduce this uncertainty, we then introduce a matching formalism which allows a generated event sample to simultaneously reproduce any infrared safe distribution calculated at leading or next-to-leading order in perturbation theory, up to sub-leading corrections. To enable a more universal definition of perturbative calculations, we also propose a more general definition of the hadronization cutoff. Finally, we present an implementation of some of these ideas for final-state gluon showers, in a code dubbed VINCIA.