Abstract
Composite-particle form factors are studied in the limit of large momentum transfer . It is shown that in models with spinor constituents and either scalar or guage vector gluons, the meson electromagnetic form factor factorizes at large and is given by independent light-cone expansions on the initial and final meson legs. The coefficient functions are shown to satisfy a Callan-Symanzik equation. When specialized to quantum chromodynamics, this equation leads to the asymptotic formula of Brodsky and Lepage for the pion electromagnetic form factor. The nucleon form factors , are also considered. It is shown that momentum flows which contribute to subdominant logarithms in vitiate a conventional renormalization-group interpretation for this form factor. For large , the electric form factor fails to factorize, so that a renormalization-group treatment seems even more unlikely in this case.
- Received 27 August 1979
DOI:https://doi.org/10.1103/PhysRevD.21.1636
©1980 American Physical Society