Gluon Helicity Delta G from a Universality Class of Operators on a Lattice

Abstract

We show that the total gluon helicity $ΔG$ in a polarized nucleon can be calculated on a Euclidean lattice through a universality class of QCD operators that describe the helicity or polarization of the onshell gluon radiation. We in particular find some operators whose matrix elements in a nucleon of momentum $P^z$ are directly related to $ΔG$ with only power-law $(1/P^z)^n (n\ge 2)$ corrections.

11 pages