Abstract
We give a pedagogical discussion of the physics underlying dispersion relation-derived parametrizations of form factors describing and . Moments of the dispersion relations are shown to provide substantially tighter constraints on the form factor describing than the unweighted dispersion relation alone. Heavy quark spin symmetry relations between the and form factors enable such constraints to be tightened even further.
- Received 18 February 1997
DOI:https://doi.org/10.1103/PhysRevD.56.303
©1997 American Physical Society