Skip to content

Counting Form Factors of Twist-Two Operators

Xiangdong Ji, Richard F. Lebed

hep-pharXiv:hep-ph/0012160

Abstract

We present a simple method to count the number of hadronic form factors based on the partial wave formalism and crossing symmetry. In particular, we show that the number of independent nucleon form factors of spin-n, twist-2 operators (the vector current and energy-momentum tensor being special examples) is n+1. These generalized form factors define the generalized (off-forward) parton distributions that have been studied extensively in the recent literature. In proving this result, we also show how the JPC rules for onium states arise in the helicity formalism.

Create a lesson