Accounting for coherence in interjet E_t flow: a case study

TL;DR

Understanding interjet $E_t$ flow and rapidity-gap observables requires accounting for coherent soft-gluon emissions beyond independent primary emissions, even at single-logarithmic accuracy. Approach: analyze the colour structure of soft radiation from a four-parton antenna and perform single-logarithmic resummation, including virtual corrections and colour-interference effects, with relevance to energy-flow observables in multi-jet topologies. The coherence among arbitrarily complex ensembles of large-angle soft gluons and their colour content influences interjet energy distributions, with examination in the simpler 2-jet context to reveal novel QCD dynamics. These results provide theoretical tools for precision predictions of interjet energy distributions at hadron colliders and inform broader colour-flow modelling in multi-jet events.

Abstract

Recently, interest has developed in the distribution of interjet energy flows, with for example the leading-log calculation of the highly non-trivial colour structure of primary emissions in 4-jet systems. Here we point out however that at leading-log level it is insufficient to consider only multiple primary emission from the underlying hard antenna -- additionally, one must take into account the coherent structure of emission from arbitrarily complicated ensembles of large-angle soft gluons. Similar considerations apply to certain definitions of rapidity gaps based on energy flow. We examine this new class of terms in the simpler context of 2-jet events, and discover features that point at novel aspects of the QCD dynamics.