Logarithmically-accurate showers with massive quarks

TL;DR

This paper develops and validates a new class of final-state shower algorithms that incorporate quark masses and achieve high logarithmic accuracy, validated through fixed-order and all-order comparisons.

Contribution

It introduces mass-aware PanScales final-state showers with next-to-leading logarithmic accuracy, maintaining original accuracy for mass-insensitive observables.

Findings

Validated shower algorithms against fixed-order calculations up to second order in alpha_s.

Performed all-order comparisons with analytic resummed calculations for various observables.

Included phenomenological studies using LEP data to demonstrate practical relevance.

Abstract

We formulate PanScales final-state showers that account for quark masses and achieve next-to-leading logarithmic accuracy, while preserving the original accuracy of the showers for observables where the mass of the quarks is irrelevant. We validate the accuracy of the shower algorithms by performing fixed-order tests up to second order in the strong coupling constant, and all-order comparisons to (semi-)analytic resummed calculations for a series of observables, including Lund-tree shapes, non-global energy flows and Lund sub-jet multiplicities. We also include some phenomenological studies using LEP data.