Jet Mass Spectra in Higgs + One Jet at NNLL

TL;DR

This paper presents a precise calculation of the jet mass spectrum in Higgs plus one jet events at the LHC at NNLL accuracy, incorporating effects of jet vetoes and non-global logarithms, and compares results with experimental data.

Contribution

It provides the first complete NNLL calculation of the exclusive jet mass spectrum in Higgs plus one jet events, including effects of jet vetoes and non-global logarithms.

Findings

Jet mass spectrum depends on kinematics, jet algorithm, and size R.

Quark and gluon jets show distinguishable mass spectra.

Hadronization and underlying event effects are analyzed.

Abstract

The invariant mass of a jet is a benchmark variable describing the structure of jets at the LHC. We calculate the jet mass spectrum for Higgs plus one jet at the LHC at next-to-next-to-leading logarithmic (NNLL) order using a factorization formula. At this order, the cross section becomes sensitive to perturbation theory at the soft m_jet^2/p_T^jet scale. Our calculation is exclusive and uses the 1-jettiness global event shape to implement a veto on additional jets. The dominant dependence on the jet veto is removed by normalizing the spectrum, leaving residual dependence from non-global logarithms depending on the ratio of the jet mass and jet veto variables. For our exclusive jet cross section these non-global logarithms are parametrically smaller than in the inclusive case, allowing us to obtain a complete NNLL result. Results for the dependence of the jet mass spectrum on the kinematics, jet algorithm, and jet size R are given. Using individual partonic channels we illustrate the difference between the jet mass spectra for quark and gluon jets. We also study the effect of hadronization and underlying event on the jet mass in PYTHIA. To highlight the similarity of inclusive and exclusive jet mass spectra, a comparison to LHC data is presented.