Non-perturbative QCD effects in jets at hadron colliders

TL;DR

This paper analyzes non-perturbative QCD effects on jet observables at hadron colliders, examining how hadronisation and underlying event contributions depend on jet radius, parton properties, and jet algorithms, supported by analytic models and simulations.

Contribution

It provides a detailed analysis of how non-perturbative effects vary with jet radius and parton characteristics, offering predictions and measurements to improve precision in jet studies.

Findings

Hadronisation corrections scale as 1/R at small R

Underlying event contributions grow with R^2

Results are consistent across different jet algorithms

Abstract

We discuss non-perturbative QCD contributions to jet observables, computing their dependence on the jet radius R, and on the colour and transverse momentum of the parton initiating the jet. We show, using analytic QCD models of power corrections as well as Monte Carlo simulations, that hadronisation corrections grow at small values of R, behaving as 1/R, while underlying event contributions grow with the jet area as R^2. We highlight the connection between hadronisation corrections to jets and those for event shapes in e^+e^- and DIS; we note the limited dependence of our results on the choice of jet algorithm; finally, we propose several measurements in the context of which to test or implement our predictions. The results presented here reinforce the motivation for the use of a range of R values, as well as a plurality of infrared-safe jet algorithms, in precision jet studies at hadron colliders.