TMD factorization and the gluon distribution in high energy QCD

Abstract

This paper is a part of a series of works where we in detail examine the concept of Transverse Momentum Dependent (TMD), or k_T, factorization, which is frequently encountered in the literature and is widely used in the phenomenological applications of QCD at very high energies. We address the question of what exactly factorization is, as it is meant in different contexts and formalisms, and we compare the formalisms to each other. We clarify some basic concepts regarding factorization and how it exactly is applied in high energy QCD, and we make important notes on some key and fundamental points that are often overlooked. We offer an extensive analysis of single inclusive particle production, and we analyze the TMD gluon distribution that plays a pivotal role in high energy QCD.

80 pages v2: Few typos corrected, and references added

References in corpus (19)

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Cited by in corpus (10)

• Azimuthal asymmetries for quark pair production in pA collisions
• Dynamical entropy of dense QCD states
• Transition between soft physics at LHC and low-x physics at HERA
• TMD PDFs: a Monte Carlo implementation for the sea quark distribution
• Loop space and evolution of the light-like Wilson polygons
• Nonperturbative corrections and showering in NLO-matched event generators
• Inability to find justification of a $k_T$-factorization formula by following chains of citations
• Next-to-Leading Order correction to inclusive particle spectra in the Color Glass Condensate framework
• TMD parton densities in associated real and virtual photon and jet production at LHC
• TMD PDFs in Drell-Yan lepton pair production at LHC