  Two- and three-particle distribution amplitudes of heavy pseudoscalar mesons
of well-defined geometric twist are introduced. They are obtained from
appropriately parametrized vacuum-to-meson matrix elements by applying those
twist projectors which determine the enclosed light-cone operators of definite
geometric twist and, in addition, observing the heavy quark constraint.
Comparing these distribution amplitudes with the conventional ones of dynamical
twist we derive relations between them, partially being of Wandzura-Wilczek
type; also sum rules of Burkhardt-Cottingham type are derived.The derivation is
performed for the (double) Mellin moments and then re-summed to the non-local
distribution amplitudes. Furthermore, a parametrization of vacuum-to-meson
matrix elements for non-local operators off the light-cone in terms of
distribution amplitudes accompanying independent kinematical structures is
derived.
