Transverse-Distance Dependent Parton Densities in the Large-$x$ Regime

Abstract

QCD factorization approach in the field-theoretic description of the semi-inclusive hadronic processes in the large Bjorken $x$ approximation implies extraction of the three-dimensional parton distribution functions as a convolution of a collinear jet function and soft transverse-distance dependent (TDD) function defined as a vacuum average of a partially light-like Wilson loop. The soft function can be interpreted, therefore, as an element of generalized loop space. A class of classically conformal-invariant transformations of the elements of this space is generated by the non-local area derivative operator which corresponds to a diffeomorphism in the loop space and determines equations of motion, the latter being associated with the rapidity evolution of the soft TDD functions. We propose a large-$x$ TDD factorization framework and discuss practical applications of this approach to the phenomenology of the TDDs accessible in future experimental programs at the Jefferson Lab 12 GeV and the Electron-Ion Collider.

6 pages; based on invited talk presented at "Lightcone 2013+: Venturing off the LightCone - Local vs. Global Features", Skiathos, Greece, 20-24 May 2013; submitted to Few Body Systems

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Cited by in corpus (2)

• On Geometric Scaling of Light-Like Wilson Polygons: Higher Orders in ${\alpha }_s$
• Fréchet derivative for light-like Wilson Loops