QCD resummation for light-particle jets

TL;DR

This paper develops QCD-based evolution equations for light-particle jets, successfully describing their invariant-mass and energy profiles, and matching experimental data from Tevatron and LHC, aiding in heavy particle identification.

Contribution

It introduces novel evolution equations for light-quark and gluon jets' invariant-mass and energy profiles within QCD resummation, aligning theory with experimental observations.

Findings

Jet invariant-mass distribution vanishes at small mass and peaks at higher mass with energy.

Energy accumulates faster in light-quark jets than in gluon jets.

Model matches Tevatron and LHC data, enabling jet composition analysis.

Abstract

We construct an evolution equation for the invariant-mass distribution of light-quark and gluon jets in the framework of QCD resummation. The solution of the evolution equation exhibits a behavior consistent with Tevatron CDF data: the jet distribution vanishes in the small invariant-mass limit, and its peak moves toward the high invariant-mass region with the jet energy. We also construct an evolution equation for the energy profile of the light-quark and gluon jets in the similar framework. The solution shows that the energy accumulates faster within a light-quark jet cone than within a gluon jet cone. The jet energy profile convoluted with hard scattering and parton distribution functions matches well with the Tevatron CDF and the large-hadron-collider (LHC) CMS data. Moreover, comparison with the CDF and CMS data implies that jets with large (small) transverse momentum are mainly composed of the light-quark (gluon) jets. At last, we discuss the application of the above solutions for the light-particle jets to the identification of highly-boosted heavy particles produced at LHC.