Assessing Uncertainties in Parton Showers at Double Logarithmic Accuracy for Jet Quenching Studies

TL;DR

This study evaluates uncertainties in parton shower simulations at double logarithmic accuracy and their effects on jet quenching, emphasizing the influence of evolution variables and kinematic schemes on key observables in high-energy collisions.

Contribution

We developed a toy-model for vacuum parton showers with various evolution variables to analyze their impact on jet quenching simulations.

Findings

Variation in evolution variables significantly affects key distributions.

Choice of ordering variable impacts large-angle emissions more than kinematic schemes.

Jet quenching sensitivity depends on the ordering prescription, especially in thin media.

Abstract

This paper assesses the uncertainties inherent to parton shower simulations at double logarithmic accuracy, with a focus on their impact on jet quenching studies in high-energy heavy-ion collisions. For that purpose, we developed a massless quark-initiated vacuum parton shower toy-model with different evolution variables, such as inverse formation time, invariant squared mass, and squared opening angle. In addition to the effects of varying the ordering variable we further examine their corresponding kinematic reconstructions. The results highlight how these variations influence key distributions, including the number of splittings, angular and transverse momentum distribution of subsequent emissions. We also analyse the Lund distributions and their average trajectories, revealing that the choice of ordering variable has a significantly greater impact on the vacuum parton shower evolution than the kinematic scheme, particularly in large-angle emission regions. When a simple jet quenching model based on decoherence is implemented, we observe that the fraction of quenched events is sensitive to the ordering prescription, especially for the first splitting and thin media, highlighting the need for a deeper understanding of the branching process in the presence of an extended QCD media.