Counting Rule for Hadronic Light-Cone Wave Functions

Abstract

We introduce a systematic way to write down the Fock components of a hadronic light-cone wave function with $n$ partons and orbital angular momentum projection $l_z$. We show that the wave function amplitude ${\psi }_n(x_i,k_{i\perp },l_{zi})$ has a leading behavior $1/(k_{\perp }^2{)}^{[n+|l_z|+\min (n^{\prime }+|l_z^{\prime }|)]/2-1}$ when all parton transverse momenta are uniformly large, where $n^{\prime }$ and $l_z^{\prime }$ are the number of partons and orbital angular momentum projection, respectively, of an amplitude that mixes under renormalization. The result can be used as a constraint in modeling the hadronic light-cone wave functions. We also derive a generalized counting rule for hard exclusive processes involving parton orbital angular momentum and hadron helicity flip.

Comments: 7 pages, no figure