Factorization of Jet Cross Sections in Heavy-Ion Collisions

Area of Science:

• High-energy nuclear physics
• Quantum Chromodynamics (QCD)
• Particle physics phenomenology

Background:

• Understanding jet interactions within the hot and dense QCD medium is crucial for heavy-ion physics.
• Existing factorization formalisms in proton-proton collisions need adaptation for the nuclear environment.
• The properties of quark and gluon jets can differ significantly when traversing the medium.

Purpose of the Study:

• To propose a new phenomenological approach for QCD factorization of jet cross sections in heavy-ion collisions.
• To introduce and determine medium-modified jet functions capturing jet-medium interactions.
• To investigate the differential suppression of quark and gluon jets and its relation to jet radius.

Main Methods:

• Extension of proton-proton factorization formalism to heavy-ion collisions.
• Introduction of medium-modified jet functions to model jet interactions with the QCD medium.
• Global analysis using Monte Carlo sampling to determine jet functions from LHC inclusive jet data.
• Analysis of the nuclear modification factor for inclusive jets.

Main Results:

• Gluon jets exhibit significantly greater suppression in the QCD medium compared to quark jets.
• The dependence of jet suppression on the jet radius is directly linked to the relative suppression of quark and gluon jets.
• The newly determined medium-modified jet functions provide a reliable description of experimental data.

Conclusions:

• The proposed phenomenological approach successfully establishes QCD factorization for jets in heavy-ion collisions.
• The findings highlight distinct medium interactions for quark and gluon jets, with implications for their suppression.
• This framework offers a potential improvement for extracting properties of the QCD medium from experimental data.