Non-Global Correlations in Collider Physics

Abstract

Despite their importance for precision QCD calculations, correlations between in- and out-of-jet regions of phase space have never directly been observed. These so-called non-global effects are present generically whenever a collider physics measurement is not explicitly dependent on radiation throughout the entire phase space. In this paper, we introduce a novel procedure based on mutual information, which allows us to isolate these non-global correlations between measurements made in different regions of phase space. We study this procedure both analytically and in Monte Carlo simulations in the context of observables measured on hadronic final states produced in $e^{+}{e}^{-}$ collisions, though it is more widely applicable. The procedure exploits the sensitivity of soft radiation at large angles to non-global correlations, and we calculate these correlations through next-to-leading logarithmic accuracy. The bulk of these non-global correlations are found to be described in Monte Carlo simulation. They increase by the inclusion of non-perturbative effects, which we show can be incorporated in our calculation through the use of a model shape function. This procedure illuminates the source of non-global correlations and has connections more broadly to fundamental quantities in quantum field theory.

8 pages, 5 figures plus Appendices; v2 PRD version, added paragraph mentioning fixed-order corrections

References in corpus (16)

• An Introduction to PYTHIA 8.2
• Treating the b quark distribution function with reliable uncertainties
• Gaining (Mutual) Information about Quark/Gluon Discrimination
• A simple shower and matching algorithm
• Momentum Flow Correlations from Event Shapes: Factorized Soft Gluons and Soft-Collinear Effective Theory
• On jet mass distributions in Z+jet and dijet processes at the LHC
• Non-Global Logarithms, Factorization, and the Soft Substructure of Jets
• On QCD resummation with kt clustering
• Jet Substructure Without Trees
• Non-global Logarithms at 3 Loops, 4 Loops, 5 Loops and Beyond
• Non-global logarithms at finite Nc beyond leading order
• Non-Global Logarithms in Filtered Jet Algorithms
• Aspects of Jets at 100 TeV
• The Edge of Jets and Subleading Non-Global Logs
• The First Calculation of Fractional Jets
• Helicity-Dependent Showers and Matching with VINCIA

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• New Angles on Energy Correlation Functions
• Disentangling Heavy Flavor at Colliders
• Measurement of groomed event shape observables in deep-inelastic electron-proton scattering at HERA
• Effective Field Theories for the LHC