Abstract

We address the issues of clustering and non-global logarithms for jet shapes in the process of production of a Higgs/vector boson associated with a single hard jet at hadron colliders. We perform an analytical fixed-order calculation up to second order in the coupling as well as an all-orders estimation for the specific invariant mass distribution of the highest-p_t jet, for various jet algorithms. Our results are derived in the eikonal (soft) limit and are valid up to next-to-leading logarithmic accuracy. We perform a matching of the resummed distribution to next-to-leading order results from MCFM and compare our findings with the outputs of the Monte Carlo event generators Pythia 8 and Herwig 7. After accounting for non-perturbative effects we compare our results with available experimental data from the CMS collaboration for the Z + jet production. We find good agreement over a wide range of the observable.

Highlights

  • For these aspects pave the way for a deeper insight into QCD processes, a better control of theoretical uncertainties, and a precise quantification of missing higher-order contributions and their significance, all of which are issues not very clear in Monte Carlo event generators

  • To ensure a proper next-toleading logarithmic (NLL) resummation its distribution must carefully be treated for a class of large single logarithms known as non-global logarithms (NGLs), which are related to secondary non-Abelian emissions of soft gluons [1,2]

  • In this work we study the jet mass distribution in the process of production of a single jet associated with a vector boson (γ, Z or W ) or a Higgs boson H at the Large Hadron Collider (LHC)

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Summary

Introduction

In this paper we shed light on the resummation of large logarithms that arise due to a miscancellation of soft and collinear singularities between real emissions and their corresponding virtual corrections. To ensure a proper NLL resummation its distribution must carefully be treated for a class of large single logarithms known as non-global logarithms (NGLs), which are related to secondary non-Abelian emissions of soft gluons [1,2] Another type of large single logarithms known as clustering logarithms (CLs) [3,4], related to primary gluon emissions off the hard Born configuration, needs to be resummed when the jets are reconstructed using jet algorithms such as kt [5,6] and Cambridge–Aachen (C–A) [7,8]. [11], the jet mass distribution was calculated at NLL accuracy combined with next-to-leading order (NLO) results in Z + jet and di-jet processes at hadron colliders, for jets defined with the anti-kt clustering algorithm. We compare the NLL-resummed and NLO-matched result for the jet mass distribution, which includes the resummed global and nonglobal (NGLs and CLs) form factors convoluted with the Born cross-section and corrected for NLO effects for each.

Processes and kinematics
Jet mass observable and jet algorithms
Jet mass distribution
Fixed-order calculation
Resummed global result
Two-gluon emission
Clustering logarithms
Non-global logarithms
Anti-kt clustering algorithm
All-orders treatment of CLs and NGLs
Comparison to Pythia 8 and Herwig 7 parton showers
Matching to fixed order
Comparison to CMS data
Conclusions

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