Speaker
Description
We perform a systematic study on the twist-3 gluon distribution and fragmentation
functions which appear in the collinear twist-3 factorization for hard inclusive
processes. Three types of twist-3 distribution and fragmentation functions,
i.e., intrinsic, kinematical and dynamical ones, which are necessary to describe
all kinds of twist-3 cross sections, are related to each other by the operator
identities based on the QCD equation of motion and the Lorentz invariance
properties of the correlation functions. We derive the exact relations for all
twist-3 gluonic distribution and fragmentation functions for a spin-1/2 hadron.
Those relations allow one to express intrinsic and kinematical twist-3 gluon
functions in terms of the twist-2 and dynamical twist-3 functions, which provides
a basis for the renormalization of intrinsic and kinematical twist-3 functions.
In addition, those model independent relations are crucial to guarantee gauge
invariance and frame independence properties of the twist-3 cross sections.
