Gauge invariance of transverse momentum dependent distributions at small <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:math>

Abstract

The interplay between the small-$x$ limit of QCD amplitudes and QCD factorization at moderate $x$ has been studied extensively in recent years. It was finally shown that semiclassical formulations of small-$x$ physics can have the form of an infinite twist framework involving transverse momentum dependent distributions in the eikonal limit. In this work, we demonstrate that small-$x$ distributions can be formulated in terms of transverse gauge links. This allows, in particular, for direct and efficient decompositions of observables into subamplitudes involving gauge-invariant suboperators which span parton distributions.

Topics & Concepts