Ji X, Ma JP, Yuan F. Generalized counting rule for hard exclusive processes.
PHYSICAL REVIEW LETTERS 2003;
90:241601. [PMID:
12857185 DOI:
10.1103/physrevlett.90.241601]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2003] [Indexed: 05/24/2023]
Abstract
We derive a generalized counting rule for hard exclusive processes involving parton orbital angular momentum and hadron helicity flip. We start with a systematic way to enumerate 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 perpendicular ),l(zi)) has a leading behavior 1/(k(2)( perpendicular ))[n(+|l(z)|+min(n(')+|l(')(z)|)]/2-1) when all parton transverse momenta are uniformly large, where n(') and l(')(z) are the number of partons and orbital angular momentum projection, respectively, of an amplitude that mixes under renormalization. Besides the generalized counting rule, the result can be used as a constraint in modeling the hadronic light-cone wave functions.
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