Propagation of Uncertainty in a Parton Shower

TL;DR

This paper introduces a method to propagate uncertainties in parton shower simulations using alternate event weights, enabling systematic analysis of model variations without modifying the existing code.

Contribution

It presents a novel, broadly applicable technique for uncertainty propagation in parton shower algorithms that requires no changes to the simulation implementation.

Findings

Allows systematic uncertainty quantification in parton showers

Applicable to a wide range of shower algorithms

Does not require modifications to existing code

Abstract

Presented here is a technique of propagating uncertainties through the parton shower by means of an alternate event weight. This technique provides a mechanism to systematically quantify the effect of variations of certain components of the parton shower leading to a novel approach to probing the physics implemented in a parton shower code and understanding its limitations. Further, this approach can be applied to a large class of parton shower algorithms and requires no changes to the underlying implementation.