Abstract
Hadron pair production in the region where the c.m. energy is much smaller than the photon virtuality can be described in a factorized form, as the convolution of a partonic handbag diagram and generalized distribution amplitudes which are new nonperturbative functions describing the exclusive fragmentation of a quark-antiquark pair into two hadrons. Scaling behavior and a selection rule on photon helicity are signatures of this mechanism. The case where is a pion is emphasized.
- Received 19 May 1998
DOI:https://doi.org/10.1103/PhysRevLett.81.1782
©1998 American Physical Society